stfrtime function not returning proper results through sqldf package in R

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stfrtime function not returning proper results through sqldf package in R

Manohar Reddy
Hi ,



  I have data something looks like below (or PFA), but when I’m extracting
month  using *strftime*  function through *sqldf* library ,it’s returning
below results but it’s not returning exact results ,it supposed to return
 05,05,05,06,06,06.Can anyone please guide me how to do that with *strftime*
function.



Thanks in advance.



Quiries :


library(scales)

# load data:
log <- data.frame(Date =
c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013/06/05","2013/06/07"),
  Quantity = c(9,1,15,4,5,17,18))


# convert date variable from factor to date format:
log$Date <- as.Date(log$Date,
  "%Y/%m/%d") # tabulate all the options here
str(log)







Manu.

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Re: stfrtime function not returning proper results through sqldf package in R

Jeff Newmiller
This question is missing pieces... the example is incomplete.
--
Sent from my phone. Please excuse my brevity.

On September 15, 2016 9:35:45 PM PDT, Manohar Reddy <[hidden email]> wrote:

>Hi ,
>
>
>
>I have data something looks like below (or PFA), but when I’m
>extracting
>month  using *strftime*  function through *sqldf* library ,it’s
>returning
>below results but it’s not returning exact results ,it supposed to
>return
>05,05,05,06,06,06.Can anyone please guide me how to do that with
>*strftime*
>function.
>
>
>
>Thanks in advance.
>
>
>
>Quiries :
>
>
>library(scales)
>
># load data:
>log <- data.frame(Date =
>c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013/06/05","2013/06/07"),
>  Quantity = c(9,1,15,4,5,17,18))
>
>
># convert date variable from factor to date format:
>log$Date <- as.Date(log$Date,
>  "%Y/%m/%d") # tabulate all the options here
>str(log)
>
>
>
>
>
>
>
>Manu.
>
>
>------------------------------------------------------------------------
>
>______________________________________________
>[hidden email] mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: stfrtime function not returning proper results through sqldf package in R

Manohar Reddy
Jeff,



  Thanks,my question is when I’m using strftime function in sqldf package
it’s not returning the results which has supposed to return ,now how can I
get the excat month from my sample data with strftime function through
sqldf package ?



Manu.

On Fri, Sep 16, 2016 at 11:32 AM, Jeff Newmiller <[hidden email]>
wrote:

> This question is missing pieces... the example is incomplete.
> --
> Sent from my phone. Please excuse my brevity.
>
> On September 15, 2016 9:35:45 PM PDT, Manohar Reddy <
> [hidden email]> wrote:
> >Hi ,
> >
> >
> >
> >I have data something looks like below (or PFA), but when I’m
> >extracting
> >month  using *strftime*  function through *sqldf* library ,it’s
> >returning
> >below results but it’s not returning exact results ,it supposed to
> >return
> >05,05,05,06,06,06.Can anyone please guide me how to do that with
> >*strftime*
> >function.
> >
> >
> >
> >Thanks in advance.
> >
> >
> >
> >Quiries :
> >
> >
> >library(scales)
> >
> ># load data:
> >log <- data.frame(Date =
> >c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","
> 2013/06/02","2013/06/05","2013/06/07"),
> >  Quantity = c(9,1,15,4,5,17,18))
> >
> >
> ># convert date variable from factor to date format:
> >log$Date <- as.Date(log$Date,
> >  "%Y/%m/%d") # tabulate all the options here
> >str(log)
> >
> >
> >
> >
> >
> >
> >
> >Manu.
> >
> >
> >------------------------------------------------------------------------
> >
> >______________________________________________
> >[hidden email] mailing list -- To UNSUBSCRIBE and more, see
> >https://stat.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide
> >http://www.R-project.org/posting-guide.html
> >and provide commented, minimal, self-contained, reproducible code.
>
>


--


Thanks,
Manohar Reddy P
+91-9705302062.

        [[alternative HTML version deleted]]

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: stfrtime function not returning proper results through sqldf package in R

PIKAL Petr
In reply to this post by Manohar Reddy
Hi

Hm
> format(log$Date, "%m")
[1] "05" "05" "05" "06" "06" "06" "06"
> strftime(log$Date, "%m")
[1] "05" "05" "05" "06" "06" "06" "06"
>

works for me.

Just a blind guess, is an object date somwhere in your environment?

Cheers
Petr


> -----Original Message-----
> From: R-help [mailto:[hidden email]] On Behalf Of Manohar
> Reddy
> Sent: Friday, September 16, 2016 6:36 AM
> To: R-help <[hidden email]>
> Subject: [R] stfrtime function not returning proper results through sqldf
> package in R
>
> Hi ,
>
>
>
>   I have data something looks like below (or PFA), but when I’m extracting
> month  using *strftime*  function through *sqldf* library ,it’s returning
> below results but it’s not returning exact results ,it supposed to return
> 05,05,05,06,06,06.Can anyone please guide me how to do that with
> *strftime* function.
>
>
>
> Thanks in advance.
>
>
>
> Quiries :
>
>
> library(scales)
>
> # load data:
> log <- data.frame(Date =
> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013
> /06/05","2013/06/07"),
>   Quantity = c(9,1,15,4,5,17,18))
>
>
> # convert date variable from factor to date format:
> log$Date <- as.Date(log$Date,
>   "%Y/%m/%d") # tabulate all the options here
> str(log)
>
>
>
>
>
>
>
> Manu.

________________________________
Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.

V případě, že je tento e-mail součástí obchodního jednání:
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- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.

This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
If you received this e-mail by mistake, please immediately inform its sender. Delete the contents of this e-mail with all attachments and its copies from your system.
If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a contract in any time, for any reason, and without stating any reasoning.
- if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
- the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
- the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.
______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: stfrtime function not returning proper results through sqldf package in R

Manohar Reddy
Hi Petr,



 Thanks, For me also it’s working fine when I directly used that function
 but when I call strftime function through sqldf package it’s returning NA
values (PFA) ,but my requirement is I need to do that only sqldf as I’m
writing some “T sql ” queries against on the dataset.



Manu.

On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr <[hidden email]> wrote:

> Hi
>
> Hm
> > format(log$Date, "%m")
> [1] "05" "05" "05" "06" "06" "06" "06"
> > strftime(log$Date, "%m")
> [1] "05" "05" "05" "06" "06" "06" "06"
> >
>
> works for me.
>
> Just a blind guess, is an object date somwhere in your environment?
>
> Cheers
> Petr
>
>
> > -----Original Message-----
> > From: R-help [mailto:[hidden email]] On Behalf Of Manohar
> > Reddy
> > Sent: Friday, September 16, 2016 6:36 AM
> > To: R-help <[hidden email]>
> > Subject: [R] stfrtime function not returning proper results through sqldf
> > package in R
> >
> > Hi ,
> >
> >
> >
> >   I have data something looks like below (or PFA), but when I’m
> extracting
> > month  using *strftime*  function through *sqldf* library ,it’s returning
> > below results but it’s not returning exact results ,it supposed to return
> > 05,05,05,06,06,06.Can anyone please guide me how to do that with
> > *strftime* function.
> >
> >
> >
> > Thanks in advance.
> >
> >
> >
> > Quiries :
> >
> >
> > library(scales)
> >
> > # load data:
> > log <- data.frame(Date =
> > c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013
> > /06/05","2013/06/07"),
> >   Quantity = c(9,1,15,4,5,17,18))
> >
> >
> > # convert date variable from factor to date format:
> > log$Date <- as.Date(log$Date,
> >   "%Y/%m/%d") # tabulate all the options here
> > str(log)
> >
> >
> >
> >
> >
> >
> >
> > Manu.
>
> ________________________________
> Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
> určeny pouze jeho adresátům.
> Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie
> vymažte ze svého systému.
> Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email
> jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
> Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi
> či zpožděním přenosu e-mailu.
>
> V případě, že je tento e-mail součástí obchodního jednání:
> - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
> smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
> - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout;
> Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany
> příjemce s dodatkem či odchylkou.
> - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
> výslovným dosažením shody na všech jejích náležitostech.
> - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn
> nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto
> emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich
> existence je adresátovi či osobě jím zastoupené známá.
>
> This e-mail and any documents attached to it may be confidential and are
> intended only for its intended recipients.
> If you received this e-mail by mistake, please immediately inform its
> sender. Delete the contents of this e-mail with all attachments and its
> copies from your system.
> If you are not the intended recipient of this e-mail, you are not
> authorized to use, disseminate, copy or disclose this e-mail in any manner.
> The sender of this e-mail shall not be liable for any possible damage
> caused by modifications of the e-mail or by delay with transfer of the
> email.
>
> In case that this e-mail forms part of business dealings:
> - the sender reserves the right to end negotiations about entering into a
> contract in any time, for any reason, and without stating any reasoning.
> - if the e-mail contains an offer, the recipient is entitled to
> immediately accept such offer; The sender of this e-mail (offer) excludes
> any acceptance of the offer on the part of the recipient containing any
> amendment or variation.
> - the sender insists on that the respective contract is concluded only
> upon an express mutual agreement on all its aspects.
> - the sender of this e-mail informs that he/she is not authorized to enter
> into any contracts on behalf of the company except for cases in which
> he/she is expressly authorized to do so in writing, and such authorization
> or power of attorney is submitted to the recipient or the person
> represented by the recipient, or the existence of such authorization is
> known to the recipient of the person represented by the recipient.
>


--


Thanks,
Manohar Reddy P
+91-9705302062.

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

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Re: stfrtime function not returning proper results through sqldf package in R

PIKAL Petr
Hi

Most probably there is some syntactic suger how to correctly formulate sql query.

> sqldf('select Date, strftime("Date", "%m") from log')
        Date strftime("Date", "%m")
1 2013-05-25                   <NA>
2 2013-05-28                   <NA>
3 2013-05-31                   <NA>
4 2013-06-01                   <NA>
5 2013-06-02                   <NA>
6 2013-06-05                   <NA>
7 2013-06-07                   <NA>
> sqldf('select Date, format("Date", "%m") from log')
Error in sqliteSendQuery(con, statement, bind.data) :
  error in statement: no such function: format
>

format(sqldf("select Date from log"), "%m")

This one however works.

Cheers
Petr

From: Manohar Reddy [mailto:[hidden email]]
Sent: Friday, September 16, 2016 11:55 AM
To: PIKAL Petr <[hidden email]>
Cc: R-help <[hidden email]>
Subject: Re: [R] stfrtime function not returning proper results through sqldf package in R


Hi Petr,

 Thanks, For me also it’s working fine when I directly used that function  but when I call strftime function through sqldf package it’s returning NA values (PFA) ,but my requirement is I need to do that only sqldf as I’m writing some “T sql ” queries against on the dataset.

Manu.

On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr <[hidden email]<mailto:[hidden email]>> wrote:
Hi

Hm
> format(log$Date, "%m")
[1] "05" "05" "05" "06" "06" "06" "06"
> strftime(log$Date, "%m")
[1] "05" "05" "05" "06" "06" "06" "06"
>

works for me.

Just a blind guess, is an object date somwhere in your environment?

Cheers
Petr


> -----Original Message-----
> From: R-help [mailto:[hidden email]<mailto:[hidden email]>] On Behalf Of Manohar
> Reddy
> Sent: Friday, September 16, 2016 6:36 AM
> To: R-help <[hidden email]<mailto:[hidden email]>>
> Subject: [R] stfrtime function not returning proper results through sqldf
> package in R
>
> Hi ,
>
>
>
>   I have data something looks like below (or PFA), but when I’m extracting
> month  using *strftime*  function through *sqldf* library ,it’s returning
> below results but it’s not returning exact results ,it supposed to return
> 05,05,05,06,06,06.Can anyone please guide me how to do that with
> *strftime* function.
>
>
>
> Thanks in advance.
>
>
>
> Quiries :
>
>
> library(scales)
>
> # load data:
> log <- data.frame(Date =
> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013
> /06/05","2013/06/07"),
>   Quantity = c(9,1,15,4,5,17,18))
>
>
> # convert date variable from factor to date format:
> log$Date <- as.Date(log$Date,
>   "%Y/%m/%d") # tabulate all the options here
> str(log)
>
>
>
>
>
>
>
> Manu.

________________________________
Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.

V případě, že je tento e-mail součástí obchodního jednání:
- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.

This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
If you received this e-mail by mistake, please immediately inform its sender. Delete the contents of this e-mail with all attachments and its copies from your system.
If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a contract in any time, for any reason, and without stating any reasoning.
- if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
- the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
- the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.



--


Thanks,
Manohar Reddy P
+91-9705302062.

________________________________
Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.

V případě, že je tento e-mail součástí obchodního jednání:
- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.

This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
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If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
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- if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
- the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
- the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.

        [[alternative HTML version deleted]]

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Re: stfrtime function not returning proper results through sqldf package in R

Peter Dalgaard-2
Presumably, sqldf does not know about Date object so passes an integer that gets interpreted as who knows what...

This seems to work:

> df <- data.frame(date=as.character(Sys.Date()+seq(0,180,,10)))
> cbind(df, sqldf("select strftime( '%m', date) from df"))
         date strftime( '%m', date)
1  2016-09-16                    09
2  2016-10-06                    10
3  2016-10-26                    10
4  2016-11-15                    11
5  2016-12-05                    12
6  2016-12-25                    12
7  2017-01-14                    01
8  2017-02-03                    02
9  2017-02-23                    02
10 2017-03-15                    03

-pd



On 16 Sep 2016, at 13:48 , PIKAL Petr <[hidden email]> wrote:

> Hi
>
> Most probably there is some syntactic suger how to correctly formulate sql query.
>
>> sqldf('select Date, strftime("Date", "%m") from log')
>        Date strftime("Date", "%m")
> 1 2013-05-25                   <NA>
> 2 2013-05-28                   <NA>
> 3 2013-05-31                   <NA>
> 4 2013-06-01                   <NA>
> 5 2013-06-02                   <NA>
> 6 2013-06-05                   <NA>
> 7 2013-06-07                   <NA>
>> sqldf('select Date, format("Date", "%m") from log')
> Error in sqliteSendQuery(con, statement, bind.data) :
>  error in statement: no such function: format
>>
>
> format(sqldf("select Date from log"), "%m")
>
> This one however works.
>
> Cheers
> Petr
>
> From: Manohar Reddy [mailto:[hidden email]]
> Sent: Friday, September 16, 2016 11:55 AM
> To: PIKAL Petr <[hidden email]>
> Cc: R-help <[hidden email]>
> Subject: Re: [R] stfrtime function not returning proper results through sqldf package in R
>
>
> Hi Petr,
>
> Thanks, For me also it’s working fine when I directly used that function  but when I call strftime function through sqldf package it’s returning NA values (PFA) ,but my requirement is I need to do that only sqldf as I’m writing some “T sql ” queries against on the dataset.
>
> Manu.
>
> On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr <[hidden email]<mailto:[hidden email]>> wrote:
> Hi
>
> Hm
>> format(log$Date, "%m")
> [1] "05" "05" "05" "06" "06" "06" "06"
>> strftime(log$Date, "%m")
> [1] "05" "05" "05" "06" "06" "06" "06"
>>
>
> works for me.
>
> Just a blind guess, is an object date somwhere in your environment?
>
> Cheers
> Petr
>
>
>> -----Original Message-----
>> From: R-help [mailto:[hidden email]<mailto:[hidden email]>] On Behalf Of Manohar
>> Reddy
>> Sent: Friday, September 16, 2016 6:36 AM
>> To: R-help <[hidden email]<mailto:[hidden email]>>
>> Subject: [R] stfrtime function not returning proper results through sqldf
>> package in R
>>
>> Hi ,
>>
>>
>>
>>  I have data something looks like below (or PFA), but when I’m extracting
>> month  using *strftime*  function through *sqldf* library ,it’s returning
>> below results but it’s not returning exact results ,it supposed to return
>> 05,05,05,06,06,06.Can anyone please guide me how to do that with
>> *strftime* function.
>>
>>
>>
>> Thanks in advance.
>>
>>
>>
>> Quiries :
>>
>>
>> library(scales)
>>
>> # load data:
>> log <- data.frame(Date =
>> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013
>> /06/05","2013/06/07"),
>>  Quantity = c(9,1,15,4,5,17,18))
>>
>>
>> # convert date variable from factor to date format:
>> log$Date <- as.Date(log$Date,
>>  "%Y/%m/%d") # tabulate all the options here
>> str(log)
>>
>>
>>
>>
>>
>>
>>
>> Manu.
>
> ________________________________
> Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
> Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
> Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
> Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.
>
> V případě, že je tento e-mail součástí obchodního jednání:
> - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
> - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
> - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
> - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.
>
> This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
> If you received this e-mail by mistake, please immediately inform its sender. Delete the contents of this e-mail with all attachments and its copies from your system.
> If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
> The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.
>
> In case that this e-mail forms part of business dealings:
> - the sender reserves the right to end negotiations about entering into a contract in any time, for any reason, and without stating any reasoning.
> - if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
> - the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
> - the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.
>
>
>
> --
>
>
> Thanks,
> Manohar Reddy P
> +91-9705302062.
>
> ________________________________
> Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
> Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
> Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
> Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.
>
> V případě, že je tento e-mail součástí obchodního jednání:
> - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
> - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
> - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
> - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.
>
> This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
> If you received this e-mail by mistake, please immediately inform its sender. Delete the contents of this e-mail with all attachments and its copies from your system.
> If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
> The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.
>
> In case that this e-mail forms part of business dealings:
> - the sender reserves the right to end negotiations about entering into a contract in any time, for any reason, and without stating any reasoning.
> - if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
> - the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
> - the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> [hidden email] mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: [hidden email]  Priv: [hidden email]

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
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Re: stfrtime function not returning proper results through sqldf package in R

PIKAL Petr
Hi Peter

The devil is in detail

Data from OP had different format and was transferred to Date object by as.Date, which results in incorrect values (and NA if not transferred)
df <- data.frame(Date = c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02",
"2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
df$Date<-as.Date(df$Date)
cbind(df, sqldf("select strftime( '%m', Date) from df"))

Data formatted according to your example transferred to Date object by as data, again incorrect result
df2 <- data.frame(Date = c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
df2$Date<-as.Date(df2$Date)
cbind(df2, sqldf("select strftime( '%m', Date) from df2"))

Data formatted according to your example but **not** changed to Dates, correct result
df3 <- data.frame(Date = c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
cbind(df3, sqldf("select strftime( '%m', Date) from df3"))

so sqldf is a bit peculiar about required input values and does not know how to handle Date objects.

Cheers
Petr


> -----Original Message-----
> From: peter dalgaard [mailto:[hidden email]]
> Sent: Friday, September 16, 2016 2:45 PM
> To: PIKAL Petr <[hidden email]>
> Cc: Manohar Reddy <[hidden email]>; R-help <r-help@r-
> project.org>
> Subject: Re: [R] stfrtime function not returning proper results through sqldf
> package in R
>
> Presumably, sqldf does not know about Date object so passes an integer that
> gets interpreted as who knows what...
>
> This seems to work:
>
> > df <- data.frame(date=as.character(Sys.Date()+seq(0,180,,10)))
> > cbind(df, sqldf("select strftime( '%m', date) from df"))
>          date strftime( '%m', date)
> 1  2016-09-16                    09
> 2  2016-10-06                    10
> 3  2016-10-26                    10
> 4  2016-11-15                    11
> 5  2016-12-05                    12
> 6  2016-12-25                    12
> 7  2017-01-14                    01
> 8  2017-02-03                    02
> 9  2017-02-23                    02
> 10 2017-03-15                    03
>
> -pd
>
>
>
> On 16 Sep 2016, at 13:48 , PIKAL Petr <[hidden email]> wrote:
>
> > Hi
> >
> > Most probably there is some syntactic suger how to correctly formulate sql
> query.
> >
> >> sqldf('select Date, strftime("Date", "%m") from log')
> >        Date strftime("Date", "%m")
> > 1 2013-05-25                   <NA>
> > 2 2013-05-28                   <NA>
> > 3 2013-05-31                   <NA>
> > 4 2013-06-01                   <NA>
> > 5 2013-06-02                   <NA>
> > 6 2013-06-05                   <NA>
> > 7 2013-06-07                   <NA>
> >> sqldf('select Date, format("Date", "%m") from log')
> > Error in sqliteSendQuery(con, statement, bind.data) :
> >  error in statement: no such function: format
> >>
> >
> > format(sqldf("select Date from log"), "%m")
> >
> > This one however works.
> >
> > Cheers
> > Petr
> >
> > From: Manohar Reddy [mailto:[hidden email]]
> > Sent: Friday, September 16, 2016 11:55 AM
> > To: PIKAL Petr <[hidden email]>
> > Cc: R-help <[hidden email]>
> > Subject: Re: [R] stfrtime function not returning proper results
> > through sqldf package in R
> >
> >
> > Hi Petr,
> >
> > Thanks, For me also it’s working fine when I directly used that function  but
> when I call strftime function through sqldf package it’s returning NA values
> (PFA) ,but my requirement is I need to do that only sqldf as I’m writing some
> “T sql ” queries against on the dataset.
> >
> > Manu.
> >
> > On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr
> <[hidden email]<mailto:[hidden email]>> wrote:
> > Hi
> >
> > Hm
> >> format(log$Date, "%m")
> > [1] "05" "05" "05" "06" "06" "06" "06"
> >> strftime(log$Date, "%m")
> > [1] "05" "05" "05" "06" "06" "06" "06"
> >>
> >
> > works for me.
> >
> > Just a blind guess, is an object date somwhere in your environment?
> >
> > Cheers
> > Petr
> >
> >
> >> -----Original Message-----
> >> From: R-help
> >> [mailto:[hidden email]<mailto:r-help-bounces@r-project.
> >> org>] On Behalf Of Manohar Reddy
> >> Sent: Friday, September 16, 2016 6:36 AM
> >> To: R-help <[hidden email]<mailto:[hidden email]>>
> >> Subject: [R] stfrtime function not returning proper results through
> >> sqldf package in R
> >>
> >> Hi ,
> >>
> >>
> >>
> >>  I have data something looks like below (or PFA), but when I’m
> >> extracting month  using *strftime*  function through *sqldf* library
> >> ,it’s returning below results but it’s not returning exact results
> >> ,it supposed to return 05,05,05,06,06,06.Can anyone please guide me
> >> how to do that with
> >> *strftime* function.
> >>
> >>
> >>
> >> Thanks in advance.
> >>
> >>
> >>
> >> Quiries :
> >>
> >>
> >> library(scales)
> >>
> >> # load data:
> >> log <- data.frame(Date =
> >> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2
> >> 013
> >> /06/05","2013/06/07"),
> >>  Quantity = c(9,1,15,4,5,17,18))
> >>
> >>
> >> # convert date variable from factor to date format:
> >> log$Date <- as.Date(log$Date,
> >>  "%Y/%m/%d") # tabulate all the options here
> >> str(log)
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Manu.
> >
> > ________________________________
> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
> určeny pouze jeho adresátům.
> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie
> vymažte ze svého systému.
> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento
> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
> modifikacemi či zpožděním přenosu e-mailu.
> >
> > V případě, že je tento e-mail součástí obchodního jednání:
> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy,
> a to z jakéhokoliv důvodu i bez uvedení důvodu.
> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze
> strany příjemce s dodatkem či odchylkou.
> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným
> dosažením shody na všech jejích náležitostech.
> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
> předloženy nebo jejich existence je adresátovi či osobě jím zastoupené
> známá.
> >
> > This e-mail and any documents attached to it may be confidential and are
> intended only for its intended recipients.
> > If you received this e-mail by mistake, please immediately inform its
> sender. Delete the contents of this e-mail with all attachments and its copies
> from your system.
> > If you are not the intended recipient of this e-mail, you are not authorized
> to use, disseminate, copy or disclose this e-mail in any manner.
> > The sender of this e-mail shall not be liable for any possible damage caused
> by modifications of the e-mail or by delay with transfer of the email.
> >
> > In case that this e-mail forms part of business dealings:
> > - the sender reserves the right to end negotiations about entering into a
> contract in any time, for any reason, and without stating any reasoning.
> > - if the e-mail contains an offer, the recipient is entitled to immediately
> accept such offer; The sender of this e-mail (offer) excludes any acceptance
> of the offer on the part of the recipient containing any amendment or
> variation.
> > - the sender insists on that the respective contract is concluded only upon
> an express mutual agreement on all its aspects.
> > - the sender of this e-mail informs that he/she is not authorized to enter
> into any contracts on behalf of the company except for cases in which he/she
> is expressly authorized to do so in writing, and such authorization or power of
> attorney is submitted to the recipient or the person represented by the
> recipient, or the existence of such authorization is known to the recipient of
> the person represented by the recipient.
> >
> >
> >
> > --
> >
> >
> > Thanks,
> > Manohar Reddy P
> > +91-9705302062.
> >
> > ________________________________
> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
> určeny pouze jeho adresátům.
> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie
> vymažte ze svého systému.
> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento
> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
> modifikacemi či zpožděním přenosu e-mailu.
> >
> > V případě, že je tento e-mail součástí obchodního jednání:
> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy,
> a to z jakéhokoliv důvodu i bez uvedení důvodu.
> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze
> strany příjemce s dodatkem či odchylkou.
> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným
> dosažením shody na všech jejích náležitostech.
> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
> předloženy nebo jejich existence je adresátovi či osobě jím zastoupené
> známá.
> >
> > This e-mail and any documents attached to it may be confidential and are
> intended only for its intended recipients.
> > If you received this e-mail by mistake, please immediately inform its
> sender. Delete the contents of this e-mail with all attachments and its copies
> from your system.
> > If you are not the intended recipient of this e-mail, you are not authorized
> to use, disseminate, copy or disclose this e-mail in any manner.
> > The sender of this e-mail shall not be liable for any possible damage caused
> by modifications of the e-mail or by delay with transfer of the email.
> >
> > In case that this e-mail forms part of business dealings:
> > - the sender reserves the right to end negotiations about entering into a
> contract in any time, for any reason, and without stating any reasoning.
> > - if the e-mail contains an offer, the recipient is entitled to immediately
> accept such offer; The sender of this e-mail (offer) excludes any acceptance
> of the offer on the part of the recipient containing any amendment or
> variation.
> > - the sender insists on that the respective contract is concluded only upon
> an express mutual agreement on all its aspects.
> > - the sender of this e-mail informs that he/she is not authorized to enter
> into any contracts on behalf of the company except for cases in which he/she
> is expressly authorized to do so in writing, and such authorization or power of
> attorney is submitted to the recipient or the person represented by the
> recipient, or the existence of such authorization is known to the recipient of
> the person represented by the recipient.
> >
> >     [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > [hidden email] mailing list -- To UNSUBSCRIBE and more, see
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000
> Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: [hidden email]  Priv: [hidden email]


________________________________
Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům.
Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému.
Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu.

V případě, že je tento e-mail součástí obchodního jednání:
- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky ze strany příjemce s dodatkem či odchylkou.
- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve výslovným dosažením shody na všech jejích náležitostech.
- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly adresátovi tohoto emailu případně osobě, kterou adresát zastupuje, předloženy nebo jejich existence je adresátovi či osobě jím zastoupené známá.

This e-mail and any documents attached to it may be confidential and are intended only for its intended recipients.
If you received this e-mail by mistake, please immediately inform its sender. Delete the contents of this e-mail with all attachments and its copies from your system.
If you are not the intended recipient of this e-mail, you are not authorized to use, disseminate, copy or disclose this e-mail in any manner.
The sender of this e-mail shall not be liable for any possible damage caused by modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a contract in any time, for any reason, and without stating any reasoning.
- if the e-mail contains an offer, the recipient is entitled to immediately accept such offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part of the recipient containing any amendment or variation.
- the sender insists on that the respective contract is concluded only upon an express mutual agreement on all its aspects.
- the sender of this e-mail informs that he/she is not authorized to enter into any contracts on behalf of the company except for cases in which he/she is expressly authorized to do so in writing, and such authorization or power of attorney is submitted to the recipient or the person represented by the recipient, or the existence of such authorization is known to the recipient of the person represented by the recipient.
______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: stfrtime function not returning proper results through sqldf package in R

Jeff Newmiller
SQLite only understands certain fundamental data types, and neither Date nor POSIXct types are among them. They get stored as their internal numeric representations.

The internal numeric representations of Date and POSIXct are incompatible. You are sending Dates to SQLite and trying to then interpret it as POSIXct by handing that numeric to strftime.

Note that within R the Date and POSIXct types are made sort-of compatible by internal checking of class attributes that are not stored in SQLite. They are still only sort-of compatible because Date has no concept of time zone and always assumes GMT rather than local time when being converted.

I recommend retrieving the stored Date value as a Date value into R so that strftime can recognize how to interpret it. If you need to handle time as well as date you may find that converting to character first before converting to POSIXct with an appropriate time zone behaves with least surprises.
--
Sent from my phone. Please excuse my brevity.

On September 16, 2016 6:23:48 AM PDT, PIKAL Petr <[hidden email]> wrote:

>Hi Peter
>
>The devil is in detail
>
>Data from OP had different format and was transferred to Date object by
>as.Date, which results in incorrect values (and NA if not transferred)
>df <- data.frame(Date =
>c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02",
>"2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
>df$Date<-as.Date(df$Date)
>cbind(df, sqldf("select strftime( '%m', Date) from df"))
>
>Data formatted according to your example transferred to Date object by
>as data, again incorrect result
>df2 <- data.frame(Date =
>c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>df2$Date<-as.Date(df2$Date)
>cbind(df2, sqldf("select strftime( '%m', Date) from df2"))
>
>Data formatted according to your example but **not** changed to Dates,
>correct result
>df3 <- data.frame(Date =
>c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>cbind(df3, sqldf("select strftime( '%m', Date) from df3"))
>
>so sqldf is a bit peculiar about required input values and does not
>know how to handle Date objects.
>
>Cheers
>Petr
>
>
>> -----Original Message-----
>> From: peter dalgaard [mailto:[hidden email]]
>> Sent: Friday, September 16, 2016 2:45 PM
>> To: PIKAL Petr <[hidden email]>
>> Cc: Manohar Reddy <[hidden email]>; R-help <r-help@r-
>> project.org>
>> Subject: Re: [R] stfrtime function not returning proper results
>through sqldf
>> package in R
>>
>> Presumably, sqldf does not know about Date object so passes an
>integer that
>> gets interpreted as who knows what...
>>
>> This seems to work:
>>
>> > df <- data.frame(date=as.character(Sys.Date()+seq(0,180,,10)))
>> > cbind(df, sqldf("select strftime( '%m', date) from df"))
>>          date strftime( '%m', date)
>> 1  2016-09-16                    09
>> 2  2016-10-06                    10
>> 3  2016-10-26                    10
>> 4  2016-11-15                    11
>> 5  2016-12-05                    12
>> 6  2016-12-25                    12
>> 7  2017-01-14                    01
>> 8  2017-02-03                    02
>> 9  2017-02-23                    02
>> 10 2017-03-15                    03
>>
>> -pd
>>
>>
>>
>> On 16 Sep 2016, at 13:48 , PIKAL Petr <[hidden email]> wrote:
>>
>> > Hi
>> >
>> > Most probably there is some syntactic suger how to correctly
>formulate sql
>> query.
>> >
>> >> sqldf('select Date, strftime("Date", "%m") from log')
>> >        Date strftime("Date", "%m")
>> > 1 2013-05-25                   <NA>
>> > 2 2013-05-28                   <NA>
>> > 3 2013-05-31                   <NA>
>> > 4 2013-06-01                   <NA>
>> > 5 2013-06-02                   <NA>
>> > 6 2013-06-05                   <NA>
>> > 7 2013-06-07                   <NA>
>> >> sqldf('select Date, format("Date", "%m") from log')
>> > Error in sqliteSendQuery(con, statement, bind.data) :
>> >  error in statement: no such function: format
>> >>
>> >
>> > format(sqldf("select Date from log"), "%m")
>> >
>> > This one however works.
>> >
>> > Cheers
>> > Petr
>> >
>> > From: Manohar Reddy [mailto:[hidden email]]
>> > Sent: Friday, September 16, 2016 11:55 AM
>> > To: PIKAL Petr <[hidden email]>
>> > Cc: R-help <[hidden email]>
>> > Subject: Re: [R] stfrtime function not returning proper results
>> > through sqldf package in R
>> >
>> >
>> > Hi Petr,
>> >
>> > Thanks, For me also it’s working fine when I directly used that
>function  but
>> when I call strftime function through sqldf package it’s returning NA
>values
>> (PFA) ,but my requirement is I need to do that only sqldf as I’m
>writing some
>> “T sql ” queries against on the dataset.
>> >
>> > Manu.
>> >
>> > On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr
>> <[hidden email]<mailto:[hidden email]>> wrote:
>> > Hi
>> >
>> > Hm
>> >> format(log$Date, "%m")
>> > [1] "05" "05" "05" "06" "06" "06" "06"
>> >> strftime(log$Date, "%m")
>> > [1] "05" "05" "05" "06" "06" "06" "06"
>> >>
>> >
>> > works for me.
>> >
>> > Just a blind guess, is an object date somwhere in your environment?
>> >
>> > Cheers
>> > Petr
>> >
>> >
>> >> -----Original Message-----
>> >> From: R-help
>> >>
>[mailto:[hidden email]<mailto:r-help-bounces@r-project.
>> >> org>] On Behalf Of Manohar Reddy
>> >> Sent: Friday, September 16, 2016 6:36 AM
>> >> To: R-help <[hidden email]<mailto:[hidden email]>>
>> >> Subject: [R] stfrtime function not returning proper results
>through
>> >> sqldf package in R
>> >>
>> >> Hi ,
>> >>
>> >>
>> >>
>> >>  I have data something looks like below (or PFA), but when I’m
>> >> extracting month  using *strftime*  function through *sqldf*
>library
>> >> ,it’s returning below results but it’s not returning exact results
>> >> ,it supposed to return 05,05,05,06,06,06.Can anyone please guide
>me
>> >> how to do that with
>> >> *strftime* function.
>> >>
>> >>
>> >>
>> >> Thanks in advance.
>> >>
>> >>
>> >>
>> >> Quiries :
>> >>
>> >>
>> >> library(scales)
>> >>
>> >> # load data:
>> >> log <- data.frame(Date =
>> >>
>c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2
>> >> 013
>> >> /06/05","2013/06/07"),
>> >>  Quantity = c(9,1,15,4,5,17,18))
>> >>
>> >>
>> >> # convert date variable from factor to date format:
>> >> log$Date <- as.Date(log$Date,
>> >>  "%Y/%m/%d") # tabulate all the options here
>> >> str(log)
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>
>> >> Manu.
>> >
>> > ________________________________
>> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a
>jsou
>> určeny pouze jeho adresátům.
>> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>kopie
>> vymažte ze svého systému.
>> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni
>tento
>> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>> modifikacemi či zpožděním přenosu e-mailu.
>> >
>> > V případě, že je tento e-mail součástí obchodního jednání:
>> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>smlouvy,
>> a to z jakéhokoliv důvodu i bez uvedení důvodu.
>> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí
>nabídky ze
>> strany příjemce s dodatkem či odchylkou.
>> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>výslovným
>> dosažením shody na všech jejích náležitostech.
>> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>> předloženy nebo jejich existence je adresátovi či osobě jím
>zastoupené
>> známá.
>> >
>> > This e-mail and any documents attached to it may be confidential
>and are
>> intended only for its intended recipients.
>> > If you received this e-mail by mistake, please immediately inform
>its
>> sender. Delete the contents of this e-mail with all attachments and
>its copies
>> from your system.
>> > If you are not the intended recipient of this e-mail, you are not
>authorized
>> to use, disseminate, copy or disclose this e-mail in any manner.
>> > The sender of this e-mail shall not be liable for any possible
>damage caused
>> by modifications of the e-mail or by delay with transfer of the
>email.
>> >
>> > In case that this e-mail forms part of business dealings:
>> > - the sender reserves the right to end negotiations about entering
>into a
>> contract in any time, for any reason, and without stating any
>reasoning.
>> > - if the e-mail contains an offer, the recipient is entitled to
>immediately
>> accept such offer; The sender of this e-mail (offer) excludes any
>acceptance
>> of the offer on the part of the recipient containing any amendment or
>> variation.
>> > - the sender insists on that the respective contract is concluded
>only upon
>> an express mutual agreement on all its aspects.
>> > - the sender of this e-mail informs that he/she is not authorized
>to enter
>> into any contracts on behalf of the company except for cases in which
>he/she
>> is expressly authorized to do so in writing, and such authorization
>or power of
>> attorney is submitted to the recipient or the person represented by
>the
>> recipient, or the existence of such authorization is known to the
>recipient of
>> the person represented by the recipient.
>> >
>> >
>> >
>> > --
>> >
>> >
>> > Thanks,
>> > Manohar Reddy P
>> > +91-9705302062.
>> >
>> > ________________________________
>> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a
>jsou
>> určeny pouze jeho adresátům.
>> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>kopie
>> vymažte ze svého systému.
>> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni
>tento
>> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>> modifikacemi či zpožděním přenosu e-mailu.
>> >
>> > V případě, že je tento e-mail součástí obchodního jednání:
>> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>smlouvy,
>> a to z jakéhokoliv důvodu i bez uvedení důvodu.
>> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí
>nabídky ze
>> strany příjemce s dodatkem či odchylkou.
>> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>výslovným
>> dosažením shody na všech jejích náležitostech.
>> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>> předloženy nebo jejich existence je adresátovi či osobě jím
>zastoupené
>> známá.
>> >
>> > This e-mail and any documents attached to it may be confidential
>and are
>> intended only for its intended recipients.
>> > If you received this e-mail by mistake, please immediately inform
>its
>> sender. Delete the contents of this e-mail with all attachments and
>its copies
>> from your system.
>> > If you are not the intended recipient of this e-mail, you are not
>authorized
>> to use, disseminate, copy or disclose this e-mail in any manner.
>> > The sender of this e-mail shall not be liable for any possible
>damage caused
>> by modifications of the e-mail or by delay with transfer of the
>email.
>> >
>> > In case that this e-mail forms part of business dealings:
>> > - the sender reserves the right to end negotiations about entering
>into a
>> contract in any time, for any reason, and without stating any
>reasoning.
>> > - if the e-mail contains an offer, the recipient is entitled to
>immediately
>> accept such offer; The sender of this e-mail (offer) excludes any
>acceptance
>> of the offer on the part of the recipient containing any amendment or
>> variation.
>> > - the sender insists on that the respective contract is concluded
>only upon
>> an express mutual agreement on all its aspects.
>> > - the sender of this e-mail informs that he/she is not authorized
>to enter
>> into any contracts on behalf of the company except for cases in which
>he/she
>> is expressly authorized to do so in writing, and such authorization
>or power of
>> attorney is submitted to the recipient or the person represented by
>the
>> recipient, or the existence of such authorization is known to the
>recipient of
>> the person represented by the recipient.
>> >
>> >     [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > [hidden email] mailing list -- To UNSUBSCRIBE and more, see
>> > https://stat.ethz.ch/mailman/listinfo/r-help
>> > PLEASE do read the posting guide
>> > http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>>
>> --
>> Peter Dalgaard, Professor,
>> Center for Statistics, Copenhagen Business School Solbjerg Plads 3,
>2000
>> Frederiksberg, Denmark
>> Phone: (+45)38153501
>> Office: A 4.23
>> Email: [hidden email]  Priv: [hidden email]
>
>
>________________________________
>Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
>určeny pouze jeho adresátům.
>Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>kopie vymažte ze svého systému.
>Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento
>email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>modifikacemi či zpožděním přenosu e-mailu.
>
>V případě, že je tento e-mail součástí obchodního jednání:
>- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
>- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky
>ze strany příjemce s dodatkem či odchylkou.
>- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>výslovným dosažením shody na všech jejích náležitostech.
>- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>předloženy nebo jejich existence je adresátovi či osobě jím zastoupené
>známá.
>
>This e-mail and any documents attached to it may be confidential and
>are intended only for its intended recipients.
>If you received this e-mail by mistake, please immediately inform its
>sender. Delete the contents of this e-mail with all attachments and its
>copies from your system.
>If you are not the intended recipient of this e-mail, you are not
>authorized to use, disseminate, copy or disclose this e-mail in any
>manner.
>The sender of this e-mail shall not be liable for any possible damage
>caused by modifications of the e-mail or by delay with transfer of the
>email.
>
>In case that this e-mail forms part of business dealings:
>- the sender reserves the right to end negotiations about entering into
>a contract in any time, for any reason, and without stating any
>reasoning.
>- if the e-mail contains an offer, the recipient is entitled to
>immediately accept such offer; The sender of this e-mail (offer)
>excludes any acceptance of the offer on the part of the recipient
>containing any amendment or variation.
>- the sender insists on that the respective contract is concluded only
>upon an express mutual agreement on all its aspects.
>- the sender of this e-mail informs that he/she is not authorized to
>enter into any contracts on behalf of the company except for cases in
>which he/she is expressly authorized to do so in writing, and such
>authorization or power of attorney is submitted to the recipient or the
>person represented by the recipient, or the existence of such
>authorization is known to the recipient of the person represented by
>the recipient.
>______________________________________________
>[hidden email] mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

______________________________________________
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Re: stfrtime function not returning proper results through sqldf package in R

Gabor Grothendieck
To be precise it's SQLite that does not have date and time data types.
If you use an sqldf backend such as H2 that does have such types then
sqldf will pass them as such.  In the case of R's "Date" class such
objects are passed to SQLite as numbers since that is what SQLite can
understand but they are passed as dates to H2 (and other backends if
they have a date type).

Also note that after sqldf passes a date to SQLite as a number then
when SQLite passes it back to sqldf then sqldf  knows that it was
originally a date (due to the column name being the same) and coerces
it to Date class again.  In the example below sqldf passed the number
of days to 2000-01-01 since the UNIX epoch to SQLite.  SQLite then
processed it and passed it back as a number again. Then sqldf realized
that it was originally a Date because the column name is still d and
the original column d was of "Date" class and so coerces the number
from SQLite to Date.  There are a limited number of circumstances
where this heuristic works but they are sufficient that it's often
transparent even though SQLite has no date and time types.

> library(sqldf)
> DF <- data.frame(d = as.Date("2000-01-01"))
> sqldf("select d+1 as d from DF") # return next day
           d
1 2000-01-02

At the same time iif you really need to do serious date processing on
the SQL side it's much easier with an sqldf backend such as H2 that
actually supports date and time types and no heuristic is needed by
sqldf and no user workarounds on the R side are needed.


On Fri, Sep 16, 2016 at 10:15 AM, Jeff Newmiller
<[hidden email]> wrote:

> SQLite only understands certain fundamental data types, and neither Date nor POSIXct types are among them. They get stored as their internal numeric representations.
>
> The internal numeric representations of Date and POSIXct are incompatible. You are sending Dates to SQLite and trying to then interpret it as POSIXct by handing that numeric to strftime.
>
> Note that within R the Date and POSIXct types are made sort-of compatible by internal checking of class attributes that are not stored in SQLite. They are still only sort-of compatible because Date has no concept of time zone and always assumes GMT rather than local time when being converted.
>
> I recommend retrieving the stored Date value as a Date value into R so that strftime can recognize how to interpret it. If you need to handle time as well as date you may find that converting to character first before converting to POSIXct with an appropriate time zone behaves with least surprises.
> --
> Sent from my phone. Please excuse my brevity.
>
> On September 16, 2016 6:23:48 AM PDT, PIKAL Petr <[hidden email]> wrote:
>>Hi Peter
>>
>>The devil is in detail
>>
>>Data from OP had different format and was transferred to Date object by
>>as.Date, which results in incorrect values (and NA if not transferred)
>>df <- data.frame(Date =
>>c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02",
>>"2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
>>df$Date<-as.Date(df$Date)
>>cbind(df, sqldf("select strftime( '%m', Date) from df"))
>>
>>Data formatted according to your example transferred to Date object by
>>as data, again incorrect result
>>df2 <- data.frame(Date =
>>c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>>"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>>df2$Date<-as.Date(df2$Date)
>>cbind(df2, sqldf("select strftime( '%m', Date) from df2"))
>>
>>Data formatted according to your example but **not** changed to Dates,
>>correct result
>>df3 <- data.frame(Date =
>>c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>>"2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>>cbind(df3, sqldf("select strftime( '%m', Date) from df3"))
>>
>>so sqldf is a bit peculiar about required input values and does not
>>know how to handle Date objects.
>>
>>Cheers
>>Petr
>>
>>
>>> -----Original Message-----
>>> From: peter dalgaard [mailto:[hidden email]]
>>> Sent: Friday, September 16, 2016 2:45 PM
>>> To: PIKAL Petr <[hidden email]>
>>> Cc: Manohar Reddy <[hidden email]>; R-help <r-help@r-
>>> project.org>
>>> Subject: Re: [R] stfrtime function not returning proper results
>>through sqldf
>>> package in R
>>>
>>> Presumably, sqldf does not know about Date object so passes an
>>integer that
>>> gets interpreted as who knows what...
>>>
>>> This seems to work:
>>>
>>> > df <- data.frame(date=as.character(Sys.Date()+seq(0,180,,10)))
>>> > cbind(df, sqldf("select strftime( '%m', date) from df"))
>>>          date strftime( '%m', date)
>>> 1  2016-09-16                    09
>>> 2  2016-10-06                    10
>>> 3  2016-10-26                    10
>>> 4  2016-11-15                    11
>>> 5  2016-12-05                    12
>>> 6  2016-12-25                    12
>>> 7  2017-01-14                    01
>>> 8  2017-02-03                    02
>>> 9  2017-02-23                    02
>>> 10 2017-03-15                    03
>>>
>>> -pd
>>>
>>>
>>>
>>> On 16 Sep 2016, at 13:48 , PIKAL Petr <[hidden email]> wrote:
>>>
>>> > Hi
>>> >
>>> > Most probably there is some syntactic suger how to correctly
>>formulate sql
>>> query.
>>> >
>>> >> sqldf('select Date, strftime("Date", "%m") from log')
>>> >        Date strftime("Date", "%m")
>>> > 1 2013-05-25                   <NA>
>>> > 2 2013-05-28                   <NA>
>>> > 3 2013-05-31                   <NA>
>>> > 4 2013-06-01                   <NA>
>>> > 5 2013-06-02                   <NA>
>>> > 6 2013-06-05                   <NA>
>>> > 7 2013-06-07                   <NA>
>>> >> sqldf('select Date, format("Date", "%m") from log')
>>> > Error in sqliteSendQuery(con, statement, bind.data) :
>>> >  error in statement: no such function: format
>>> >>
>>> >
>>> > format(sqldf("select Date from log"), "%m")
>>> >
>>> > This one however works.
>>> >
>>> > Cheers
>>> > Petr
>>> >
>>> > From: Manohar Reddy [mailto:[hidden email]]
>>> > Sent: Friday, September 16, 2016 11:55 AM
>>> > To: PIKAL Petr <[hidden email]>
>>> > Cc: R-help <[hidden email]>
>>> > Subject: Re: [R] stfrtime function not returning proper results
>>> > through sqldf package in R
>>> >
>>> >
>>> > Hi Petr,
>>> >
>>> > Thanks, For me also it’s working fine when I directly used that
>>function  but
>>> when I call strftime function through sqldf package it’s returning NA
>>values
>>> (PFA) ,but my requirement is I need to do that only sqldf as I’m
>>writing some
>>> “T sql ” queries against on the dataset.
>>> >
>>> > Manu.
>>> >
>>> > On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr
>>> <[hidden email]<mailto:[hidden email]>> wrote:
>>> > Hi
>>> >
>>> > Hm
>>> >> format(log$Date, "%m")
>>> > [1] "05" "05" "05" "06" "06" "06" "06"
>>> >> strftime(log$Date, "%m")
>>> > [1] "05" "05" "05" "06" "06" "06" "06"
>>> >>
>>> >
>>> > works for me.
>>> >
>>> > Just a blind guess, is an object date somwhere in your environment?
>>> >
>>> > Cheers
>>> > Petr
>>> >
>>> >
>>> >> -----Original Message-----
>>> >> From: R-help
>>> >>
>>[mailto:[hidden email]<mailto:r-help-bounces@r-project.
>>> >> org>] On Behalf Of Manohar Reddy
>>> >> Sent: Friday, September 16, 2016 6:36 AM
>>> >> To: R-help <[hidden email]<mailto:[hidden email]>>
>>> >> Subject: [R] stfrtime function not returning proper results
>>through
>>> >> sqldf package in R
>>> >>
>>> >> Hi ,
>>> >>
>>> >>
>>> >>
>>> >>  I have data something looks like below (or PFA), but when I’m
>>> >> extracting month  using *strftime*  function through *sqldf*
>>library
>>> >> ,it’s returning below results but it’s not returning exact results
>>> >> ,it supposed to return 05,05,05,06,06,06.Can anyone please guide
>>me
>>> >> how to do that with
>>> >> *strftime* function.
>>> >>
>>> >>
>>> >>
>>> >> Thanks in advance.
>>> >>
>>> >>
>>> >>
>>> >> Quiries :
>>> >>
>>> >>
>>> >> library(scales)
>>> >>
>>> >> # load data:
>>> >> log <- data.frame(Date =
>>> >>
>>c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2
>>> >> 013
>>> >> /06/05","2013/06/07"),
>>> >>  Quantity = c(9,1,15,4,5,17,18))
>>> >>
>>> >>
>>> >> # convert date variable from factor to date format:
>>> >> log$Date <- as.Date(log$Date,
>>> >>  "%Y/%m/%d") # tabulate all the options here
>>> >> str(log)
>>> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> Manu.
>>> >
>>> > ________________________________
>>> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a
>>jsou
>>> určeny pouze jeho adresátům.
>>> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>>> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>>kopie
>>> vymažte ze svého systému.
>>> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni
>>tento
>>> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>>> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>>> modifikacemi či zpožděním přenosu e-mailu.
>>> >
>>> > V případě, že je tento e-mail součástí obchodního jednání:
>>> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>>smlouvy,
>>> a to z jakéhokoliv důvodu i bez uvedení důvodu.
>>> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>>> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí
>>nabídky ze
>>> strany příjemce s dodatkem či odchylkou.
>>> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>>výslovným
>>> dosažením shody na všech jejích náležitostech.
>>> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>>> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>>> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>>> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>>> předloženy nebo jejich existence je adresátovi či osobě jím
>>zastoupené
>>> známá.
>>> >
>>> > This e-mail and any documents attached to it may be confidential
>>and are
>>> intended only for its intended recipients.
>>> > If you received this e-mail by mistake, please immediately inform
>>its
>>> sender. Delete the contents of this e-mail with all attachments and
>>its copies
>>> from your system.
>>> > If you are not the intended recipient of this e-mail, you are not
>>authorized
>>> to use, disseminate, copy or disclose this e-mail in any manner.
>>> > The sender of this e-mail shall not be liable for any possible
>>damage caused
>>> by modifications of the e-mail or by delay with transfer of the
>>email.
>>> >
>>> > In case that this e-mail forms part of business dealings:
>>> > - the sender reserves the right to end negotiations about entering
>>into a
>>> contract in any time, for any reason, and without stating any
>>reasoning.
>>> > - if the e-mail contains an offer, the recipient is entitled to
>>immediately
>>> accept such offer; The sender of this e-mail (offer) excludes any
>>acceptance
>>> of the offer on the part of the recipient containing any amendment or
>>> variation.
>>> > - the sender insists on that the respective contract is concluded
>>only upon
>>> an express mutual agreement on all its aspects.
>>> > - the sender of this e-mail informs that he/she is not authorized
>>to enter
>>> into any contracts on behalf of the company except for cases in which
>>he/she
>>> is expressly authorized to do so in writing, and such authorization
>>or power of
>>> attorney is submitted to the recipient or the person represented by
>>the
>>> recipient, or the existence of such authorization is known to the
>>recipient of
>>> the person represented by the recipient.
>>> >
>>> >
>>> >
>>> > --
>>> >
>>> >
>>> > Thanks,
>>> > Manohar Reddy P
>>> > +91-9705302062.
>>> >
>>> > ________________________________
>>> > Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a
>>jsou
>>> určeny pouze jeho adresátům.
>>> > Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>>> neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>>kopie
>>> vymažte ze svého systému.
>>> > Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni
>>tento
>>> email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>>> > Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>>> modifikacemi či zpožděním přenosu e-mailu.
>>> >
>>> > V případě, že je tento e-mail součástí obchodního jednání:
>>> > - vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>>smlouvy,
>>> a to z jakéhokoliv důvodu i bez uvedení důvodu.
>>> > - a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>>> přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí
>>nabídky ze
>>> strany příjemce s dodatkem či odchylkou.
>>> > - trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>>výslovným
>>> dosažením shody na všech jejích náležitostech.
>>> > - odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>>> společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>>> zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>>> adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>>> předloženy nebo jejich existence je adresátovi či osobě jím
>>zastoupené
>>> známá.
>>> >
>>> > This e-mail and any documents attached to it may be confidential
>>and are
>>> intended only for its intended recipients.
>>> > If you received this e-mail by mistake, please immediately inform
>>its
>>> sender. Delete the contents of this e-mail with all attachments and
>>its copies
>>> from your system.
>>> > If you are not the intended recipient of this e-mail, you are not
>>authorized
>>> to use, disseminate, copy or disclose this e-mail in any manner.
>>> > The sender of this e-mail shall not be liable for any possible
>>damage caused
>>> by modifications of the e-mail or by delay with transfer of the
>>email.
>>> >
>>> > In case that this e-mail forms part of business dealings:
>>> > - the sender reserves the right to end negotiations about entering
>>into a
>>> contract in any time, for any reason, and without stating any
>>reasoning.
>>> > - if the e-mail contains an offer, the recipient is entitled to
>>immediately
>>> accept such offer; The sender of this e-mail (offer) excludes any
>>acceptance
>>> of the offer on the part of the recipient containing any amendment or
>>> variation.
>>> > - the sender insists on that the respective contract is concluded
>>only upon
>>> an express mutual agreement on all its aspects.
>>> > - the sender of this e-mail informs that he/she is not authorized
>>to enter
>>> into any contracts on behalf of the company except for cases in which
>>he/she
>>> is expressly authorized to do so in writing, and such authorization
>>or power of
>>> attorney is submitted to the recipient or the person represented by
>>the
>>> recipient, or the existence of such authorization is known to the
>>recipient of
>>> the person represented by the recipient.
>>> >
>>> >     [[alternative HTML version deleted]]
>>> >
>>> > ______________________________________________
>>> > [hidden email] mailing list -- To UNSUBSCRIBE and more, see
>>> > https://stat.ethz.ch/mailman/listinfo/r-help
>>> > PLEASE do read the posting guide
>>> > http://www.R-project.org/posting-guide.html
>>> > and provide commented, minimal, self-contained, reproducible code.
>>>
>>> --
>>> Peter Dalgaard, Professor,
>>> Center for Statistics, Copenhagen Business School Solbjerg Plads 3,
>>2000
>>> Frederiksberg, Denmark
>>> Phone: (+45)38153501
>>> Office: A 4.23
>>> Email: [hidden email]  Priv: [hidden email]
>>
>>
>>________________________________
>>Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou
>>určeny pouze jeho adresátům.
>>Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě
>>neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho
>>kopie vymažte ze svého systému.
>>Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento
>>email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat.
>>Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou
>>modifikacemi či zpožděním přenosu e-mailu.
>>
>>V případě, že je tento e-mail součástí obchodního jednání:
>>- vyhrazuje si odesílatel právo ukončit kdykoliv jednání o uzavření
>>smlouvy, a to z jakéhokoliv důvodu i bez uvedení důvodu.
>>- a obsahuje-li nabídku, je adresát oprávněn nabídku bezodkladně
>>přijmout; Odesílatel tohoto e-mailu (nabídky) vylučuje přijetí nabídky
>>ze strany příjemce s dodatkem či odchylkou.
>>- trvá odesílatel na tom, že příslušná smlouva je uzavřena teprve
>>výslovným dosažením shody na všech jejích náležitostech.
>>- odesílatel tohoto emailu informuje, že není oprávněn uzavírat za
>>společnost žádné smlouvy s výjimkou případů, kdy k tomu byl písemně
>>zmocněn nebo písemně pověřen a takové pověření nebo plná moc byly
>>adresátovi tohoto emailu případně osobě, kterou adresát zastupuje,
>>předloženy nebo jejich existence je adresátovi či osobě jím zastoupené
>>známá.
>>
>>This e-mail and any documents attached to it may be confidential and
>>are intended only for its intended recipients.
>>If you received this e-mail by mistake, please immediately inform its
>>sender. Delete the contents of this e-mail with all attachments and its
>>copies from your system.
>>If you are not the intended recipient of this e-mail, you are not
>>authorized to use, disseminate, copy or disclose this e-mail in any
>>manner.
>>The sender of this e-mail shall not be liable for any possible damage
>>caused by modifications of the e-mail or by delay with transfer of the
>>email.
>>
>>In case that this e-mail forms part of business dealings:
>>- the sender reserves the right to end negotiations about entering into
>>a contract in any time, for any reason, and without stating any
>>reasoning.
>>- if the e-mail contains an offer, the recipient is entitled to
>>immediately accept such offer; The sender of this e-mail (offer)
>>excludes any acceptance of the offer on the part of the recipient
>>containing any amendment or variation.
>>- the sender insists on that the respective contract is concluded only
>>upon an express mutual agreement on all its aspects.
>>- the sender of this e-mail informs that he/she is not authorized to
>>enter into any contracts on behalf of the company except for cases in
>>which he/she is expressly authorized to do so in writing, and such
>>authorization or power of attorney is submitted to the recipient or the
>>person represented by the recipient, or the existence of such
>>authorization is known to the recipient of the person represented by
>>the recipient.
>>______________________________________________
>>[hidden email] mailing list -- To UNSUBSCRIBE and more, see
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide
>>http://www.R-project.org/posting-guide.html
>>and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> [hidden email] mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: stfrtime function not returning proper results through sqldf package in R

Peter Dalgaard-2
In reply to this post by PIKAL Petr

On 16 Sep 2016, at 15:23 , PIKAL Petr <[hidden email]> wrote:

> Hi Peter
>
> The devil is in detail
>
> Data from OP had different format and was transferred to Date object by as.Date, which results in incorrect values (and NA if not transferred)
> df <- data.frame(Date = c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02",
> "2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
> df$Date<-as.Date(df$Date)
> cbind(df, sqldf("select strftime( '%m', Date) from df"))
>

To be fair, he actually used as.Date(...., "%Y/%m/%d"), so the values were in fact correct. The issue lay in the conversion to integer.

I can't figure out how those integers are interpreted, though:

> df <- data.frame(date=c(0,1000,2000))
> cbind(df, sqldf("select strftime( '%Y-%m-%d', date) from df"))
  date strftime( '%Y-%m-%d', date)
1    0                  -471-11-24
2 1000                  -471-08-20
3 2000                  -470-05-16

so the Epoch is nothing sensible and negative years are more than a thousand days??


--
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: [hidden email]  Priv: [hidden email]

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Re: stfrtime function not returning proper results through sqldf package in R

Manohar Reddy
First of all I would like to say thanks to everyone for sharing valuable
information, now I can able to do that if date column datatype is “Factor”
but by default the date column datatype is “POSIXct” in R ,so whenever I
want apply stfrtime function with sqldf package ,do I need to convert the
date datatype to factor ??? or is there any alternative  way?



Manu.

On Fri, Sep 16, 2016 at 9:08 PM, peter dalgaard <[hidden email]> wrote:

>
> On 16 Sep 2016, at 15:23 , PIKAL Petr <[hidden email]> wrote:
>
> > Hi Peter
> >
> > The devil is in detail
> >
> > Data from OP had different format and was transferred to Date object by
> as.Date, which results in incorrect values (and NA if not transferred)
> > df <- data.frame(Date = c("2013/05/25","2013/05/28","
> 2013/05/31","2013/06/01","2013/06/02",
> > "2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
> > df$Date<-as.Date(df$Date)
> > cbind(df, sqldf("select strftime( '%m', Date) from df"))
> >
>
> To be fair, he actually used as.Date(...., "%Y/%m/%d"), so the values were
> in fact correct. The issue lay in the conversion to integer.
>
> I can't figure out how those integers are interpreted, though:
>
> > df <- data.frame(date=c(0,1000,2000))
> > cbind(df, sqldf("select strftime( '%Y-%m-%d', date) from df"))
>   date strftime( '%Y-%m-%d', date)
> 1    0                  -471-11-24
> 2 1000                  -471-08-20
> 3 2000                  -470-05-16
>
> so the Epoch is nothing sensible and negative years are more than a
> thousand days??
>
>
> --
> Peter Dalgaard, Professor,
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Office: A 4.23
> Email: [hidden email]  Priv: [hidden email]
>
>


--


Thanks,
Manohar Reddy P
+91-9705302062.

        [[alternative HTML version deleted]]

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Re: stfrtime function not returning proper results through sqldf package in R

Jeff Newmiller
In reply to this post by Gabor Grothendieck
Yes, some of my info was outdated and misleading. :)

However, after I RTFM [1] it becomes clear that the strftime function
being invoked in the SQL statement has completely different parameters
(both ordering and interpretation) and behavior than the strftime function
in R, and that is the primary issue affecting the original question.

> library(sqldf)
Loading required package: gsubfn
Loading required package: proto
Loading required package: RSQLite
Loading required package: DBI
> Sys.setenv( TZ="GMT" )
> log <- data.frame( DateC = c( "2013/05/25", "2013/05/28", "2013/05/31","2013/06/01"
+                             , "2013/06/02", "2013/06/05", "2013/06/07" )
+                  , Quantity = c( 9, 1, 15, 4, 5, 17, 18 )
+                  , stringsAsFactors = FALSE
+                  )
> log$Date <- as.Date( log$DateC, format="%Y/%m/%d" )
> log$DateS <- as.character( log$Date, format="%Y-%m-%d" )
> str( log )
'data.frame':   7 obs. of  4 variables:
  $ DateC   : chr  "2013/05/25" "2013/05/28" "2013/05/31" "2013/06/01" ...
  $ Quantity: num  9 1 15 4 5 17 18
  $ Date    : Date, format: "2013-05-25" "2013-05-28" ...
  $ DateS   : chr  "2013-05-25" "2013-05-28" "2013-05-31" "2013-06-01" ...
> # SQLite treatment of standard date string format converts to
> # astronomical Julian Day
> sqldf( "select strftime( '%J', '1970-01-01' )" )
Loading required package: tcltk
   strftime( '%J', '1970-01-01' )
1                      2440587.5
> # SQLite strftime function can understand strings or julian day
> # SQLite does not know 'Date' column is being stored by sqldf as days
> # since 1970-01-01
> sqldf( "select Date, Date AS DateN, strftime( '%Y-%m-%d', Date+2440587.5 ) AS DateJC, Date+2440587.5 AS DateJN from log", method=c( "Date", "numeric", "character", "numeric" ) )
         Date DateN     DateJC  DateJN
1 2013-05-25 15850 2013-05-25 2456438
2 2013-05-28 15853 2013-05-28 2456441
3 2013-05-31 15856 2013-05-31 2456444
4 2013-06-01 15857 2013-06-01 2456445
5 2013-06-02 15858 2013-06-02 2456446
6 2013-06-05 15861 2013-06-05 2456449
7 2013-06-07 15863 2013-06-07 2456451
> # So, to group by month using month computed in SQLite, have to convert
> # to JD
> sqldf( "select strftime( '%m', Date+2440587.5 ) AS Month, sum(Quantity) AS SumOfQuantity from log group by Month" )
   Month SumOfQuantity
1    05            25
2    06            44
>
> # alternatively, figure out the month in R first
> log$Month <- strftime( log$Date, format="%m" )
> sqldf( "select Month, sum(Quantity) AS SumOfQuantity from log group by Month" )
   Month SumOfQuantity
1    05            25
2    06            44

---
[1] https://www.sqlite.org/lang_datefunc.html

On Fri, 16 Sep 2016, Gabor Grothendieck wrote:

> To be precise it's SQLite that does not have date and time data types.
> If you use an sqldf backend such as H2 that does have such types then
> sqldf will pass them as such.  In the case of R's "Date" class such
> objects are passed to SQLite as numbers since that is what SQLite can
> understand but they are passed as dates to H2 (and other backends if
> they have a date type).
>
> Also note that after sqldf passes a date to SQLite as a number then
> when SQLite passes it back to sqldf then sqldf  knows that it was
> originally a date (due to the column name being the same) and coerces
> it to Date class again.  In the example below sqldf passed the number
> of days to 2000-01-01 since the UNIX epoch to SQLite.  SQLite then
> processed it and passed it back as a number again. Then sqldf realized
> that it was originally a Date because the column name is still d and
> the original column d was of "Date" class and so coerces the number
> from SQLite to Date.  There are a limited number of circumstances
> where this heuristic works but they are sufficient that it's often
> transparent even though SQLite has no date and time types.
>
>> library(sqldf)
>> DF <- data.frame(d = as.Date("2000-01-01"))
>> sqldf("select d+1 as d from DF") # return next day
>           d
> 1 2000-01-02
>
> At the same time iif you really need to do serious date processing on
> the SQL side it's much easier with an sqldf backend such as H2 that
> actually supports date and time types and no heuristic is needed by
> sqldf and no user workarounds on the R side are needed.
>
>
> On Fri, Sep 16, 2016 at 10:15 AM, Jeff Newmiller
> <[hidden email]> wrote:
>> SQLite only understands certain fundamental data types, and neither Date nor POSIXct types are among them. They get stored as their internal numeric representations.
>>
>> The internal numeric representations of Date and POSIXct are incompatible. You are sending Dates to SQLite and trying to then interpret it as POSIXct by handing that numeric to strftime.
>>
>> Note that within R the Date and POSIXct types are made sort-of compatible by internal checking of class attributes that are not stored in SQLite. They are still only sort-of compatible because Date has no concept of time zone and always assumes GMT rather than local time when being converted.
>>
>> I recommend retrieving the stored Date value as a Date value into R so that strftime can recognize how to interpret it. If you need to handle time as well as date you may find that converting to character first before converting to POSIXct with an appropriate time zone behaves with least surprises.
>> --
>> Sent from my phone. Please excuse my brevity.
>>
>> On September 16, 2016 6:23:48 AM PDT, PIKAL Petr <[hidden email]> wrote:
>>> Hi Peter
>>>
>>> The devil is in detail
>>>
>>> Data from OP had different format and was transferred to Date object by
>>> as.Date, which results in incorrect values (and NA if not transferred)
>>> df <- data.frame(Date =
>>> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02",
>>> "2013/06/05","2013/06/07"), Quantity = c(9,1,15,4,5,17,18))
>>> df$Date<-as.Date(df$Date)
>>> cbind(df, sqldf("select strftime( '%m', Date) from df"))
>>>
>>> Data formatted according to your example transferred to Date object by
>>> as data, again incorrect result
>>> df2 <- data.frame(Date =
>>> c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>>> "2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>>> df2$Date<-as.Date(df2$Date)
>>> cbind(df2, sqldf("select strftime( '%m', Date) from df2"))
>>>
>>> Data formatted according to your example but **not** changed to Dates,
>>> correct result
>>> df3 <- data.frame(Date =
>>> c("2013-05-25","2013-05-28","2013-05-31","2013-06-01","2013-06-02",
>>> "2013-06-05","2013-06-07"), Quantity = c(9,1,15,4,5,17,18))
>>> cbind(df3, sqldf("select strftime( '%m', Date) from df3"))
>>>
>>> so sqldf is a bit peculiar about required input values and does not
>>> know how to handle Date objects.
>>>
>>> Cheers
>>> Petr
>>>
>>>
>>>> -----Original Message-----
>>>> From: peter dalgaard [mailto:[hidden email]]
>>>> Sent: Friday, September 16, 2016 2:45 PM
>>>> To: PIKAL Petr <[hidden email]>
>>>> Cc: Manohar Reddy <[hidden email]>; R-help <r-help@r-
>>>> project.org>
>>>> Subject: Re: [R] stfrtime function not returning proper results
>>> through sqldf
>>>> package in R
>>>>
>>>> Presumably, sqldf does not know about Date object so passes an
>>> integer that
>>>> gets interpreted as who knows what...
>>>>
>>>> This seems to work:
>>>>
>>>>> df <- data.frame(date=as.character(Sys.Date()+seq(0,180,,10)))
>>>>> cbind(df, sqldf("select strftime( '%m', date) from df"))
>>>>          date strftime( '%m', date)
>>>> 1  2016-09-16                    09
>>>> 2  2016-10-06                    10
>>>> 3  2016-10-26                    10
>>>> 4  2016-11-15                    11
>>>> 5  2016-12-05                    12
>>>> 6  2016-12-25                    12
>>>> 7  2017-01-14                    01
>>>> 8  2017-02-03                    02
>>>> 9  2017-02-23                    02
>>>> 10 2017-03-15                    03
>>>>
>>>> -pd
>>>>
>>>>
>>>>
>>>> On 16 Sep 2016, at 13:48 , PIKAL Petr <[hidden email]> wrote:
>>>>
>>>>> Hi
>>>>>
>>>>> Most probably there is some syntactic suger how to correctly
>>> formulate sql
>>>> query.
>>>>>
>>>>>> sqldf('select Date, strftime("Date", "%m") from log')
>>>>>        Date strftime("Date", "%m")
>>>>> 1 2013-05-25                   <NA>
>>>>> 2 2013-05-28                   <NA>
>>>>> 3 2013-05-31                   <NA>
>>>>> 4 2013-06-01                   <NA>
>>>>> 5 2013-06-02                   <NA>
>>>>> 6 2013-06-05                   <NA>
>>>>> 7 2013-06-07                   <NA>
>>>>>> sqldf('select Date, format("Date", "%m") from log')
>>>>> Error in sqliteSendQuery(con, statement, bind.data) :
>>>>>  error in statement: no such function: format
>>>>>>
>>>>>
>>>>> format(sqldf("select Date from log"), "%m")
>>>>>
>>>>> This one however works.
>>>>>
>>>>> Cheers
>>>>> Petr
>>>>>
>>>>> From: Manohar Reddy [mailto:[hidden email]]
>>>>> Sent: Friday, September 16, 2016 11:55 AM
>>>>> To: PIKAL Petr <[hidden email]>
>>>>> Cc: R-help <[hidden email]>
>>>>> Subject: Re: [R] stfrtime function not returning proper results
>>>>> through sqldf package in R
>>>>>
>>>>>
>>>>> Hi Petr,
>>>>>
>>>>> Thanks, For me also it?s working fine when I directly used that
>>> function  but
>>>> when I call strftime function through sqldf package it?s returning NA
>>> values
>>>> (PFA) ,but my requirement is I need to do that only sqldf as I?m
>>> writing some
>>>> ?T sql ? queries against on the dataset.
>>>>>
>>>>> Manu.
>>>>>
>>>>> On Fri, Sep 16, 2016 at 12:56 PM, PIKAL Petr
>>>> <[hidden email]<mailto:[hidden email]>> wrote:
>>>>> Hi
>>>>>
>>>>> Hm
>>>>>> format(log$Date, "%m")
>>>>> [1] "05" "05" "05" "06" "06" "06" "06"
>>>>>> strftime(log$Date, "%m")
>>>>> [1] "05" "05" "05" "06" "06" "06" "06"
>>>>>>
>>>>>
>>>>> works for me.
>>>>>
>>>>> Just a blind guess, is an object date somwhere in your environment?
>>>>>
>>>>> Cheers
>>>>> Petr
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: R-help
>>>>>>
>>> [mailto:[hidden email]<mailto:r-help-bounces@r-project.
>>>>>> org>] On Behalf Of Manohar Reddy
>>>>>> Sent: Friday, September 16, 2016 6:36 AM
>>>>>> To: R-help <[hidden email]<mailto:[hidden email]>>
>>>>>> Subject: [R] stfrtime function not returning proper results
>>> through
>>>>>> sqldf package in R
>>>>>>
>>>>>> Hi ,
>>>>>>
>>>>>>
>>>>>>
>>>>>>  I have data something looks like below (or PFA), but when I?m
>>>>>> extracting month  using *strftime*  function through *sqldf*
>>> library
>>>>>> ,it?s returning below results but it?s not returning exact results
>>>>>> ,it supposed to return 05,05,05,06,06,06.Can anyone please guide
>>> me
>>>>>> how to do that with
>>>>>> *strftime* function.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks in advance.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Quiries :
>>>>>>
>>>>>>
>>>>>> library(scales)
>>>>>>
>>>>>> # load data:
>>>>>> log <- data.frame(Date =
>>>>>>
>>> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2
>>>>>> 013
>>>>>> /06/05","2013/06/07"),
>>>>>>  Quantity = c(9,1,15,4,5,17,18))
>>>>>>
>>>>>>
>>>>>> # convert date variable from factor to date format:
>>>>>> log$Date <- as.Date(log$Date,
>>>>>>  "%Y/%m/%d") # tabulate all the options here
>>>>>> str(log)
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Manu.
>>>>>
>>>>> ________________________________
>>>>> Tento e-mail a jak?koliv k n?mu p?ipojen? dokumenty jsou d?v?rn? a
>>> jsou
>>>> ur?eny pouze jeho adres?t?m.
>>>>> Jestli?e jste obdr?el(a) tento e-mail omylem, informujte laskav?
>>>> neprodlen? jeho odes?latele. Obsah tohoto emailu i s p??lohami a jeho
>>> kopie
>>>> vyma?te ze sv?ho syst?mu.
>>>>> Nejste-li zam??len?m adres?tem tohoto emailu, nejste opr?vn?ni
>>> tento
>>>> email jakkoliv u??vat, roz?i?ovat, kop?rovat ?i zve?ej?ovat.
>>>>> Odes?latel e-mailu neodpov?d? za eventu?ln? ?kodu zp?sobenou
>>>> modifikacemi ?i zpo?d?n?m p?enosu e-mailu.
>>>>>
>>>>> V p??pad?, ?e je tento e-mail sou??st? obchodn?ho jedn?n?:
>>>>> - vyhrazuje si odes?latel pr?vo ukon?it kdykoliv jedn?n? o uzav?en?
>>> smlouvy,
>>>> a to z jak?hokoliv d?vodu i bez uveden? d?vodu.
>>>>> - a obsahuje-li nab?dku, je adres?t opr?vn?n nab?dku bezodkladn?
>>>> p?ijmout; Odes?latel tohoto e-mailu (nab?dky) vylu?uje p?ijet?
>>> nab?dky ze
>>>> strany p??jemce s dodatkem ?i odchylkou.
>>>>> - trv? odes?latel na tom, ?e p??slu?n? smlouva je uzav?ena teprve
>>> v?slovn?m
>>>> dosa?en?m shody na v?ech jej?ch n?le?itostech.
>>>>> - odes?latel tohoto emailu informuje, ?e nen? opr?vn?n uzav?rat za
>>>> spole?nost ??dn? smlouvy s v?jimkou p??pad?, kdy k tomu byl p?semn?
>>>> zmocn?n nebo p?semn? pov??en a takov? pov??en? nebo pln? moc byly
>>>> adres?tovi tohoto emailu p??padn? osob?, kterou adres?t zastupuje,
>>>> p?edlo?eny nebo jejich existence je adres?tovi ?i osob? j?m
>>> zastoupen?
>>>> zn?m?.
>>>>>
>>>>> This e-mail and any documents attached to it may be confidential
>>> and are
>>>> intended only for its intended recipients.
>>>>> If you received this e-mail by mistake, please immediately inform
>>> its
>>>> sender. Delete the contents of this e-mail with all attachments and
>>> its copies
>>>> from your system.
>>>>> If you are not the intended recipient of this e-mail, you are not
>>> authorized
>>>> to use, disseminate, copy or disclose this e-mail in any manner.
>>>>> The sender of this e-mail shall not be liable for any possible
>>> damage caused
>>>> by modifications of the e-mail or by delay with transfer of the
>>> email.
>>>>>
>>>>> In case that this e-mail forms part of business dealings:
>>>>> - the sender reserves the right to end negotiations about entering
>>> into a
>>>> contract in any time, for any reason, and without stating any
>>> reasoning.
>>>>> - if the e-mail contains an offer, the recipient is entitled to
>>> immediately
>>>> accept such offer; The sender of this e-mail (offer) excludes any
>>> acceptance
>>>> of the offer on the part of the recipient containing any amendment or
>>>> variation.
>>>>> - the sender insists on that the respective contract is concluded
>>> only upon
>>>> an express mutual agreement on all its aspects.
>>>>> - the sender of this e-mail informs that he/she is not authorized
>>> to enter
>>>> into any contracts on behalf of the company except for cases in which
>>> he/she
>>>> is expressly authorized to do so in writing, and such authorization
>>> or power of
>>>> attorney is submitted to the recipient or the person represented by
>>> the
>>>> recipient, or the existence of such authorization is known to the
>>> recipient of
>>>> the person represented by the recipient.
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>> Thanks,
>>>>> Manohar Reddy P
>>>>> +91-9705302062.
>>>>>
>>>>> ________________________________
>>>>> Tento e-mail a jak?koliv k n?mu p?ipojen? dokumenty jsou d?v?rn? a
>>> jsou
>>>> ur?eny pouze jeho adres?t?m.
>>>>> Jestli?e jste obdr?el(a) tento e-mail omylem, informujte laskav?
>>>> neprodlen? jeho odes?latele. Obsah tohoto emailu i s p??lohami a jeho
>>> kopie
>>>> vyma?te ze sv?ho syst?mu.
>>>>> Nejste-li zam??len?m adres?tem tohoto emailu, nejste opr?vn?ni
>>> tento
>>>> email jakkoliv u??vat, roz?i?ovat, kop?rovat ?i zve?ej?ovat.
>>>>> Odes?latel e-mailu neodpov?d? za eventu?ln? ?kodu zp?sobenou
>>>> modifikacemi ?i zpo?d?n?m p?enosu e-mailu.
>>>>>
>>>>> V p??pad?, ?e je tento e-mail sou??st? obchodn?ho jedn?n?:
>>>>> - vyhrazuje si odes?latel pr?vo ukon?it kdykoliv jedn?n? o uzav?en?
>>> smlouvy,
>>>> a to z jak?hokoliv d?vodu i bez uveden? d?vodu.
>>>>> - a obsahuje-li nab?dku, je adres?t opr?vn?n nab?dku bezodkladn?
>>>> p?ijmout; Odes?latel tohoto e-mailu (nab?dky) vylu?uje p?ijet?
>>> nab?dky ze
>>>> strany p??jemce s dodatkem ?i odchylkou.
>>>>> - trv? odes?latel na tom, ?e p??slu?n? smlouva je uzav?ena teprve
>>> v?slovn?m
>>>> dosa?en?m shody na v?ech jej?ch n?le?itostech.
>>>>> - odes?latel tohoto emailu informuje, ?e nen? opr?vn?n uzav?rat za
>>>> spole?nost ??dn? smlouvy s v?jimkou p??pad?, kdy k tomu byl p?semn?
>>>> zmocn?n nebo p?semn? pov??en a takov? pov??en? nebo pln? moc byly
>>>> adres?tovi tohoto emailu p??padn? osob?, kterou adres?t zastupuje,
>>>> p?edlo?eny nebo jejich existence je adres?tovi ?i osob? j?m
>>> zastoupen?
>>>> zn?m?.
>>>>>
>>>>> This e-mail and any documents attached to it may be confidential
>>> and are
>>>> intended only for its intended recipients.
>>>>> If you received this e-mail by mistake, please immediately inform
>>> its
>>>> sender. Delete the contents of this e-mail with all attachments and
>>> its copies
>>>> from your system.
>>>>> If you are not the intended recipient of this e-mail, you are not
>>> authorized
>>>> to use, disseminate, copy or disclose this e-mail in any manner.
>>>>> The sender of this e-mail shall not be liable for any possible
>>> damage caused
>>>> by modifications of the e-mail or by delay with transfer of the
>>> email.
>>>>>
>>>>> In case that this e-mail forms part of business dealings:
>>>>> - the sender reserves the right to end negotiations about entering
>>> into a
>>>> contract in any time, for any reason, and without stating any
>>> reasoning.
>>>>> - if the e-mail contains an offer, the recipient is entitled to
>>> immediately
>>>> accept such offer; The sender of this e-mail (offer) excludes any
>>> acceptance
>>>> of the offer on the part of the recipient containing any amendment or
>>>> variation.
>>>>> - the sender insists on that the respective contract is concluded
>>> only upon
>>>> an express mutual agreement on all its aspects.
>>>>> - the sender of this e-mail informs that he/she is not authorized
>>> to enter
>>>> into any contracts on behalf of the company except for cases in which
>>> he/she
>>>> is expressly authorized to do so in writing, and such authorization
>>> or power of
>>>> attorney is submitted to the recipient or the person represented by
>>> the
>>>> recipient, or the existence of such authorization is known to the
>>> recipient of
>>>> the person represented by the recipient.
>>>>>
>>>>>     [[alternative HTML version deleted]]
>>>>>
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Fwd: stfrtime function not returning proper results through sqldf package in R

Gabor Grothendieck
In reply to this post by Manohar Reddy
1. Convert the date from R's origin to the origin used by SQLite's
strftime function and then be sure you are using the correct SQLite
strftime syntax:

    library(sqldf)
    sqldf("select strftime('%m', Date + 2440588.5) month from log")

2. Alternately use the H2 backend which actually supports dates unlike
SQLite which only supports functions that interpret certain numbers
and character strings as dates.

    library(RH2) # if RH2 is loaded sqldf will default to the H2 database
    library(sqldf)
    sqldf("select month(Date) from log")

Note that the first time you use sqldf with RH2 in a session it will
load java which is time consuming but after that it should run ok.

Note: See

1. the sqldf home page which has more info on dates and times:
https://github.com/ggrothendieck/sqldf

2. the sqldf help page:
?sqldf

3. the SQLite date and time function page which explains SQLite's
strftime function
https://www.sqlite.org/lang_datefunc.html

4. the H2 documentation:
http://www.h2database.com

On Fri, Sep 16, 2016 at 12:35 AM, Manohar Reddy <[hidden email]> wrote:

> Hi ,
>
>
>
>   I have data something looks like below (or PFA), but when I’m extracting
> month  using *strftime*  function through *sqldf* library ,it’s returning
> below results but it’s not returning exact results ,it supposed to return
>  05,05,05,06,06,06.Can anyone please guide me how to do that with *strftime*
> function.
>
>
>
> Thanks in advance.
>
>
>
> Quiries :
>
>
> library(scales)
>
> # load data:
> log <- data.frame(Date =
> c("2013/05/25","2013/05/28","2013/05/31","2013/06/01","2013/06/02","2013/06/05","2013/06/07"),
>   Quantity = c(9,1,15,4,5,17,18))
>
>
> # convert date variable from factor to date format:
> log$Date <- as.Date(log$Date,
>   "%Y/%m/%d") # tabulate all the options here
> str(log)
>
>
>
>
>
>
>
> Manu.
>
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com


--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

______________________________________________
[hidden email] mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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