Re: [R] Reshape matrix from wide to long format

From: stephen sefick <ssefick_at_gmail.com>
Date: Tue, 25 Nov 2008 08:07:07 -0500

#handy if you like ggplot2 as this is required #I think this is what you want
library(reshape)
m <- matrix(1:20, nrow=4, dimnames=list(LETTERS[1:4], letters[1:5])) melt(m)

On Tue, Nov 25, 2008 at 8:01 AM, Gabor Grothendieck <ggrothendieck_at_gmail.com> wrote:
> Try this:
>
>> as.data.frame.table(m)
> Var1 Var2 Freq
> 1 A a 1
> 2 B a 2
> 3 C a 3
> 4 D a 4
> 5 A b 5
> 6 B b 6
> 7 C b 7
> 8 D b 8
> 9 A c 9
> 10 B c 10
> 11 C c 11
> 12 D c 12
> 13 A d 13
> 14 B d 14
> 15 C d 15
> 16 D d 16
> 17 A e 17
> 18 B e 18
> 19 C e 19
> 20 D e 20
>
>
> On Tue, Nov 25, 2008 at 7:19 AM, Daren Tan <daren76_at_hotmail.com> wrote:
>>
>>
>> I forgot the reshape equivalent for converting from wide to long format. Can someone help as my matrix is very big. The followin is just an example.
>>
>>> m <- matrix(1:20, nrow=4, dimnames=list(LETTERS[1:4], letters[1:5]))
>>> m
>> a b c d e
>> A 1 5 9 13 17
>> B 2 6 10 14 18
>> C 3 7 11 15 19
>> D 4 8 12 16 20
>>
>>> as.data.frame(cbind(rep(rownames(m), ncol(m)), rep(colnames(m), each=nrow(m)), c(m)))
>> V1 V2 V3
>> 1 A a 1
>> 2 B a 2
>> 3 C a 3
>> 4 D a 4
>> 5 A b 5
>> 6 B b 6
>> 7 C b 7
>> 8 D b 8
>> 9 A c 9
>> 10 B c 10
>> 11 C c 11
>> 12 D c 12
>> 13 A d 13
>> 14 B d 14
>> 15 C d 15
>> 16 D d 16
>> 17 A e 17
>> 18 B e 18
>> 19 C e 19
>> 20 D e 20
>>
>> ______________________________________________
>> R-help_at_r-project.org mailing list
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>>
>
> ______________________________________________
> R-help_at_r-project.org 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.
>

-- 
Stephen Sefick

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

								-K. Mullis

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Received on Tue 25 Nov 2008 - 13:09:16 GMT

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