[R] create a matrix with values from data.frame

[David Winsemius]

On Mar 19, 2011, at 5:29 PM, Nicolas Gutierrez wrote:

> Hello,
>
> I'm trying to create a matrix (95x55) with data from a data.frame pop:
>
> xloc yloc      go  ind    Ene     totW
> 1    23  20   516   1     0.02   20.21
> 2    23  20  1143   1     0.02   20.21
> 3    23  20   250   1     0.02   20.21
> 4    22  15   251   1     0.02   18.69
> 5    22  15   598   1     0.02   18.69
> 6    21  19   250   1     0.02   20.21
> 7    22  20   251   1     0.02   18.69
> 8    22  20   598   1     0.02   18.69
>
> where xloc is the x dimension,  yloc the y dimension, and totW the  
> values for each cell (xloc,yloc) in my matrix (55x95):
>
> I'm trying:
>
> Bio=with(pop, (table(factor(totW, levels = 1:55), factor(totW,  
> levels = 1:95))))

You probably should be using `cut` rather than `factor`. (Both will  
create factor-class variables.)  Factor will give you a different  
level at each unique value while it appears that you want integer  
valued "cuts". It's also unclear why you would be applying these cuts  
to totW twice???? You have three rows with identical (23,20) x,y  
coordinates and two each for (22,15) and (22,20), although the go  
values are different.


>
> But I don't get what I want. Hints? Thanks!

Better advice might follow if you said what you were really trying to  
do and what the final answer should look like.

>
> Nic
>
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David Winsemius, MD
West Hartford, CT