Hi:

> df$xloc <- factor(df$xloc, levels = 1:12)
> df$yloc <- factor(df$yloc, levels = 1:12)
> with(df, xtabs(yield ~ xloc + yloc))
    yloc
xloc  1  2  3  4  5  6  7  8  9 10 11 12
  1   0  0  0  0  0  0  0  0  0  0  0  0
  2   0  0  0  0  0  0  0  0  0  0  0  0
  3   0  0  0  0  0  0  0  0  0  0  0  0
  4   0  0  0  0  0  0  0  0  0  0  0  0
  5   0  0  0  0  0  0  0  0  0  0  0  0
  6   0  0  0  0  0  0  0  0  0  0  0  0
  7   0  0  0  0  0  0  0  0  0  0  0  0
  8   0  0  0  0  0  0  0  0  0  0  0  0
  9   0  0  0  0  0  0  0  0  0  0  0  0
  10  0  0  0  0  0  0  0  0  0  0  0 95
  11  0  0  0  0  0  0  0  0  0 81  0  0
  12  0  0  0  0  0  0  0  0  0  0 30  0

Dennis

On Wed, Feb 23, 2011 at 12:27 AM, Nicolas Gutierrez <nicolasg@uw.edu> wrote:

> Hi Dennis,
>
> Thanks for your quick response and sorry for not being clear. That helped,
> but I need an actual matrix of e.g., 12 x 12 and those functions give me a
> matrix with only the "filled" locations. I need a 12 by 12 matrix with sums
> (0 if there's not data and the actual sum where there is) as follows:
>
>  1 2 3 4 5 6 7 8 9 10 11 12
> 1 0 0 0 . . . . . .  0  0  0
> 2 0 0 0 .
> 3 0 0 0 .
> .
> .
> 10                  0 81  0
>
> 11                  0  0 30
> 12                 95  0  0
>
> Any hints?
>
> THANKS!!
> Nico
>
>
>
> -------- Original Message --------
> Subject:        Re: [R] sum data from data.frame in a matrix
> Date:   Wed, 23 Feb 2011 00:10:52 -0800
> From:   Dennis Murphy <djmuser@gmail.com>
> To:     Nicolas Gutierrez <nicolasg@uw.edu>
>
>
>
> Hi:
>
> ...and a second way, using the reshape2 package:
>
> library(reshape2)
> dcast(df, yloc ~ xloc, value_var = 'yield', fun = sum)
>   yloc 10 11 12
> 1   10  0 81  0
> 2   11  0  0 30
> 3   12 95  0  0
>
>
> Dennis
>
> On Tue, Feb 22, 2011 at 11:30 PM, Nicolas Gutierrez <nicolasg@uw.edu
> <mailto:nicolasg@uw.edu>> wrote:
>
>    Hi all (again),
>
>    I have a data frame "pop":
>
>       xloc  yloc  yield
>    1  10    12    95
>    2  11    10    81
>    3  12    11    20
>    4  12    11    10
>
>    And I want to get the sum of yield for the cell (pop$xloc, pop$yloc)
>    in a matrix as follows:
>
>                xloc
>              10  11  12
>           10 0   81  0
>      yloc  11 0   0   30
>           12 95  0   0
>
>
>    Any ideas? thanks!
>
>    Nico
>
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>
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>
>

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