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as.date: do not know how to convert 'mydata[1]' to class "Date"

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algotr8der

as.date: do not know how to convert 'mydata[1]' to class "Date"

This post was updated on .

I have an object, which I pull in from a csv file here jan_2011.csv

mydata <- read.csv("jan_2011.csv", header=TRUE, sep=",")

> head(mydata)
Delivery.Date Hour.Ending Repeated.Hour.Flag Settlement.Point Settlement.Point.Price
1 01/01/2011 01:00 N HB_BUSAVG 25.18
2 01/01/2011 01:00 N HB_HOUSTON 25.36
3 01/01/2011 01:00 N HB_HUBAVG 25.07
4 01/01/2011 01:00 N HB_NORTH 25.33
5 01/01/2011 01:00 N HB_SOUTH 25.12
6 01/01/2011 01:00 N HB_WEST 24.49

> str(mydata)
'data.frame': 10416 obs. of 5 variables:
$ Delivery.Date : Factor w/ 31 levels "01/01/2011","01/02/2011",..: 1 1 1 1 1 1 1 1 1 1 ...
$ Hour.Ending : Factor w/ 24 levels "01:00","02:00",..: 1 1 1 1 1 1 1 1 1 1 ...
$ Repeated.Hour.Flag : Factor w/ 1 level "N": 1 1 1 1 1 1 1 1 1 1 ...
$ Settlement.Point : Factor w/ 14 levels "HB_BUSAVG","HB_HOUSTON",..: 1 2 3 4 5 6 7 8 9 10 ...
$ Settlement.Point.Price: num 25.2 25.4 25.1 25.3 25.1 ...

I want to convert the Delivery.Date field to a date object. I tried various attempts but failed with the following:

> as.Date(mydata[1], "%m/%d/%Y")
Error in as.Date.default(mydata[1], "%m/%d/%Y") :
do not know how to convert 'mydata[1]' to class "Date"

I even tried to save the first column to a separate object and tried the same but got the same result. At this point I'm not sure how to move forward. Appreciate the help.

Ricardogg

Re: as.date: do not know how to convert 'mydata[1]' to class "Date"

This post was updated on .

For me it works like:

as.Date(paste(mydata$Delivery.Date), "%m/%d/%Y")

Hope it works,

Regards,

Ricardo

arun kirshna

Re: as.date: do not know how to convert 'mydata[1]' to class "Date"

This post has NOT been accepted by the mailing list yet.

Hi,

There is a small mistake in your code.
#My code
as.Date(mydata[,1],"%m/%d/%Y")
[1] "2011-01-01" "2011-01-01" "2011-01-01" "2011-01-01" "2011-01-01"
[6] "2011-01-01"
#your code
as.Date(mydata[1],"%m/%d/%Y")
Error in as.Date.default(mydata[1], "%m/%d/%Y") :
do not know how to convert 'mydata[1]' to class "Date"
A.K.

algotr8der

Re: as.date: do not know how to convert 'mydata[1]' to class "Date"

Thank you Ricardogg and Arun. I don't know how I missed that. Too many sleepless nights perhaps. Thank you.

Michael Weylandt

Re: as.date: do not know how to convert 'test[1]' to class "Date"

In reply to this post by algotr8der

Please don't post files to nabble in the future -- when Nabble removes
them, we then have a broken link in the real archives: dput() is much
preferred way to send data.

Anyways:

# mydata <- read.csv("http://r.789695.n4.nabble.com/file/n4638691/jan_2011.csv")
#
# dput(head(mydata, 15))

structure(list(Delivery.Date = structure(c(1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = c("01/01/2011",
"01/02/2011", "01/03/2011", "01/04/2011", "01/05/2011", "01/06/2011",
"01/07/2011", "01/08/2011", "01/09/2011", "01/10/2011", "01/11/2011",
"01/12/2011", "01/13/2011", "01/14/2011", "01/15/2011", "01/16/2011",
"01/17/2011", "01/18/2011", "01/19/2011", "01/20/2011", "01/21/2011",
"01/22/2011", "01/23/2011", "01/24/2011", "01/25/2011", "01/26/2011",
"01/27/2011", "01/28/2011", "01/29/2011", "01/30/2011", "01/31/2011"
), class = "factor"), Hour.Ending = structure(c(1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 2L), .Label = c("01:00",
"02:00", "03:00", "04:00", "05:00", "06:00", "07:00", "08:00",
"09:00", "10:00", "11:00", "12:00", "13:00", "14:00", "15:00",
"16:00", "17:00", "18:00", "19:00", "20:00", "21:00", "22:00",
"23:00", "24:00"), class = "factor"), Repeated.Hour.Flag = structure(c(1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "N",
class = "factor"),
Settlement.Point = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L,
8L, 9L, 10L, 11L, 12L, 13L, 14L, 1L), .Label = c("HB_BUSAVG",
"HB_HOUSTON", "HB_HUBAVG", "HB_NORTH", "HB_SOUTH", "HB_WEST",
"LZ_AEN", "LZ_CPS", "LZ_HOUSTON", "LZ_LCRA", "LZ_NORTH",
"LZ_RAYBN", "LZ_SOUTH", "LZ_WEST"), class = "factor"),
Settlement.Point.Price = c(25.18,
25.36, 25.07, 25.33, 25.12, 24.49, 25.2, 25.12, 25.41, 25.15,
25.32, 25.32, 25.1, 25.07, 23.84)), .Names = c("Delivery.Date",
"Hour.Ending", "Repeated.Hour.Flag", "Settlement.Point",
"Settlement.Point.Price"
), row.names = c(NA, 15L), class = "data.frame")

mydata[,1] <- as.Date(mydata[,1], format = "%m/%d/%Y")

works just fine for me. Note that you were missing a column.

On Wed, Aug 1, 2012 at 9:21 AM, algotr8der <[hidden email]> wrote:

No idea where this "ercot" thing comes from.

Best,
Michael

>
> I even tried to save the first column to a separate object and tried the
> same but got the same result. At this point I'm not sure how to move
> forward. Appreciate the help.
>
>
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/as-date-do-not-know-how-to-convert-test-1-to-class-Date-tp4638691.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] mailing list
> 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
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.

Rui Barradas

Re: as.date: do not know how to convert 'test[1]' to class "Date"

In reply to this post by algotr8der

Hello,

Try reading the data file with stringsAsFactors = FALSE, like this you
don't have character vectors, you have factors, which are coded as
consecutive integers 1, 2, etc.

?read.table
?read.csv

See in particular the argument above, stringsAsFactors

Hope this helps,

Rui Barradas

Em 01-08-2012 15:21, algotr8der escreveu:

> I have an object, which I pull in from a csv file here
> http://r.789695.n4.nabble.com/file/n4638691/jan_2011.csv jan_2011.csv
>
> mydata <- read.csv("jan_2011.csv", header=TRUE, sep=",")
>
>> head(mydata)
> Delivery.Date Hour.Ending Repeated.Hour.Flag Settlement.Point
> Settlement.Point.Price
> 1 01/01/2011 01:00 N HB_BUSAVG
> 25.18
> 2 01/01/2011 01:00 N HB_HOUSTON
> 25.36
> 3 01/01/2011 01:00 N HB_HUBAVG
> 25.07
> 4 01/01/2011 01:00 N HB_NORTH
> 25.33
> 5 01/01/2011 01:00 N HB_SOUTH
> 25.12
> 6 01/01/2011 01:00 N HB_WEST
> 24.49
>
>> str(mydata)
> 'data.frame': 10416 obs. of 5 variables:
> $ Delivery.Date : Factor w/ 31 levels "01/01/2011","01/02/2011",..:
> 1 1 1 1 1 1 1 1 1 1 ...
> $ Hour.Ending : Factor w/ 24 levels "01:00","02:00",..: 1 1 1 1 1
> 1 1 1 1 1 ...
> $ Repeated.Hour.Flag : Factor w/ 1 level "N": 1 1 1 1 1 1 1 1 1 1 ...
> $ Settlement.Point : Factor w/ 14 levels "HB_BUSAVG","HB_HOUSTON",..:
> 1 2 3 4 5 6 7 8 9 10 ...
> $ Settlement.Point.Price: num 25.2 25.4 25.1 25.3 25.1 ...
>
> I want to convert the Delivery.Date field to a date object. I tried various
> attempts but failed with the following:
>
>> as.Date(mydata[1], "%m/%d/%Y")
> Error in as.Date.default(ercot[1], "%m/%d/%Y") :
> do not know how to convert 'ercot[1]' to class "Date"
>
> I even tried to save the first column to a separate object and tried the
> same but got the same result. At this point I'm not sure how to move
> forward. Appreciate the help.
>
>
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/as-date-do-not-know-how-to-convert-test-1-to-class-Date-tp4638691.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] mailing list
> 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.