Use matrix subsetting like this:
x <- matrix(1:9,3)
rownames(x) <- letters[1:3]
colnames(x) <- LETTERS[1:3]
print(x)
usrs <- c("a","b","a")
vars <- c("C","C","A")
counts <- c(10,11,12)
x[cbind(usrs, vars)] <- counts
print(x)
Hope this helps,
Michael
On Thu, Apr 19, 2012 at 1:48 PM, Tim Stutt <[email protected]> wrote:
> I have data in the following list format:
>
> USER,VARIABLE,COUNT
> user1, var1, 3
> user1, var2, 4
> user2, var1, 7
> userN, var12, 5
>
> And would like to have it format as a matrix:
>
> var1 var2 var12
> user1 3 4
> user2 7
> userN 5
>
> What is the suggested method to do this for 1 million rows, with 12 variables
> and ~ 4,000 unique users?
>
> Thank you,
>
> Tim Stutt
> [email protected]
>
>
>
> [[alternative HTML version deleted]]
>
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