[R] Reshape matrix from wide to long format

[stephen sefick]

#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
>> 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.
>>
>
> ______________________________________________
> 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

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annoying little problems of being mammals.

								-K. Mullis