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need help reshaping table using aggregate

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Tim

need help reshaping table using aggregate

I am trying to learn how to reshape my data set. I am new to R, so please bear with me. Basically, I have the following data set:

site<-c("A","A","B","B")
bug<-c("spider","grasshopper","ladybug","stinkbug")
count<-c(2,4,6,8)
myf <- data.frame(site, bug, count)
myf

site bug count
1 A spider 2
2 A grasshopper 4
3 B ladybug 6
4 B stinkbug 8

This means that in site A, I found 2 spiders and 4 grasshopper. In site B, I found 6 ladybugs and 8 stinkbugs.

I would like to change the df to aggregate the site column and make the bugs columns so it arranged like this:

site spider grasshopper ladybug stinkbug
1 A 2 4 0 0
2 B 0 0 6 8

Rui Barradas

Re: need help reshaping table using aggregate

Hello,

Try

library(reshape2)

mlt <- melt(myf, id=c("site", "bug"), measure="count")
myf2 <- dcast(mm, site ~ bug)
myf2[is.na(myf2)] <- 0
myf2

Hope this helps,

Rui Barradas

Em 20-06-2012 19:58, Tim escreveu:

> I am trying to learn how to reshape my data set. I am new to R, so please
> bear with me. Basically, I have the following data set:
>
> site<-c("A","A","B","B")
> bug<-c("spider","grasshopper","ladybug","stinkbug")
> count<-c(2,4,6,8)
> myf <- data.frame(site, bug, count)
> myf
>
> site bug count
> 1 A spider 2
> 2 A grasshopper 4
> 3 B ladybug 6
> 4 B stinkbug 8
>
> This means that in site A, I found 2 spiders and 4 grasshopper. In site B,
> I found 6 ladybugs and 8 stinkbugs.
>
> I would like to change the df to aggregate the site column and make the bugs
> columns so it arranged like this:
>
> site spider grasshopper ladybug stinkbug
> 1 A 2 4 0 0
> 2 B 0 0 6 8
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/need-help-reshaping-table-using-aggregate-tp4634014.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: need help reshaping table using aggregate

Hello, again.

Actually, you don't need to melt the data.frame, you can directly dcast
'myf' using value.var="count".

Rui Barradas

Em 20-06-2012 20:56, Rui Barradas escreveu:

> Hello,
>
> Try
>
>
> library(reshape2)
>
> mlt <- melt(myf, id=c("site", "bug"), measure="count")
> myf2 <- dcast(mm, site ~ bug)
> myf2[is.na(myf2)] <- 0
> myf2
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 20-06-2012 19:58, Tim escreveu:
>> I am trying to learn how to reshape my data set. I am new to R, so
>> please
>> bear with me. Basically, I have the following data set:
>>
>> site<-c("A","A","B","B")
>> bug<-c("spider","grasshopper","ladybug","stinkbug")
>> count<-c(2,4,6,8)
>> myf <- data.frame(site, bug, count)
>> myf
>>
>> site bug count
>> 1 A spider 2
>> 2 A grasshopper 4
>> 3 B ladybug 6
>> 4 B stinkbug 8
>>
>> This means that in site A, I found 2 spiders and 4 grasshopper. In
>> site B,
>> I found 6 ladybugs and 8 stinkbugs.
>>
>> I would like to change the df to aggregate the site column and make
>> the bugs
>> columns so it arranged like this:
>>
>> site spider grasshopper ladybug stinkbug
>> 1 A 2 4 0 0
>> 2 B 0 0 6 8
>>
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/need-help-reshaping-table-using-aggregate-tp4634014.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.

Phil Spector

Re: need help reshaping table using aggregate

In reply to this post by Tim

Tim -
Another approach to your problem is to use xtabs:

> xtabs(count~site+bug,data=myf)
bug
site grasshopper ladybug spider stinkbug
A 4 0 2 0
B 0 6 0 8

- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
[hidden email]

On Wed, 20 Jun 2012, Tim wrote: