On Wed, Feb 08, 2012 at 03:56:12PM -0500, Sam Steingold wrote:
> To be clear, I can do that with nested for loops:
>
> v <- c("A1B2","A3C4","B5","C6A7B8")
> l <- strsplit(gsub("(.{2})","\\1,",v),",")
> d <- data.frame(A=vector(length=4,mode="integer"),
> B=vector(length=4,mode="integer"),
> C=vector(length=4,mode="integer"))
>
> for (i in 1:length(l)) {
> l1 <- l[[i]]
> for (j in 1:length(l1)) {
> d[[substring(l1[j],1,1)]][i] <- as.numeric(substring(l1[j],2,2))
> }
> }
Hi.
The inner loop may be vectorized.
d <- as.matrix(d)
for (i in 1:length(l)) {
l1 <- l[[i]]
d[i, substring(l1,1,1)] <- as.numeric(substring(l1,2,2))
}
A B C
1 1 2 0
2 3 0 4
3 0 5 0
4 7 8 6
If the number of rows of d is large, a matrix is probably
more efficient.
Hope this helps.
Petr Savicky.
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