R help - Feb 2009 - How to reshape this data frame from long to wide ?

I tried cast and melt in reshape package, but still can't convert this data
frame m

m
     [,1] [,2]
[1,] "A"  "1"
[2,] "A"  "2"
[3,] "B"  "3"
to this form.

m1
     [,1] [,2]
[1,] "A"  "B"
[2,] "1"  "3"
[3,] "2"  NA
Please help.

	[[alternative HTML version deleted]]

G'day Darren,

On Sun, 22 Feb 2009 11:23:27 +0800
Daren Tan <darentan76 at gmail.com> wrote:
> I tried cast and melt in reshape package, but still can't convert
> this data frame m
> 
> m
>      [,1] [,2]
> [1,] "A"  "1"
> [2,] "A"  "2"
> [3,] "B"  "3"
from the output, this does not look like a data frame to me but like a
matrix.
> to this form.
> 
> m1
>      [,1] [,2]
> [1,] "A"  "B"
> [2,] "1"  "3"
> [3,] "2"  NA
I don't think that this result can be achieved.  "A" and
"B" would
become the column names in the newly created data frame but not be
entries in the data frame themselves.

I presume you are looking for something like:

R> m <- data.frame(var=c("A", "A", "B"),
value=c("1", "2", "3"))
R> m
  var value
1   A     1
2   A     2
3   B     3
R> m$id <- c(1,2,1)
R> m
  var value id
1   A     1  1
2   A     2  2
3   B     3  1
R> library(reshape)
R> ( res <- cast(m, id~...) )
  id A    B
1  1 1    3
2  2 2 <NA>
R> res[,  !(names(res) %in% "id")]
  A    B
1 1    3
2 2 <NA>

HTH.

Cheers,

	Berwin

=========================== Full address ============================Berwin A
Turlach                            Tel.: +65 6516 4416 (secr)
Dept of Statistics and Applied Probability        +65 6516 6650 (self)
Faculty of Science                          FAX : +65 6872 3919       
National University of Singapore     
6 Science Drive 2, Blk S16, Level 7          e-mail: statba at nus.edu.sg
Singapore 117546                    http://www.stat.nus.edu.sg/~statba

Not completely clear what you want (it does not appear to be a
conventional reshape) but try this:
> m <- matrix(c("A", "A", "B",
"1", "2", "3"), 3, 2)
> structure(do.call(cbind, lapply(tapply(m[,2], m[,1], c), ts)), tsp = NULL,
class = NULL)
     A   B
[1,] "1" "3"
[2,] "2" NA


On Sat, Feb 21, 2009 at 10:23 PM, Daren Tan <darentan76 at gmail.com>
wrote:
> I tried cast and melt in reshape package, but still can't convert this
data
> frame m
>
> m
>     [,1] [,2]
> [1,] "A"  "1"
> [2,] "A"  "2"
> [3,] "B"  "3"
> to this form.
>
> m1
>     [,1] [,2]
> [1,] "A"  "B"
> [2,] "1"  "3"
> [3,] "2"  NA
> Please help.
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>