On 12/04/2009 02:18 PM, Lee William wrote:
Dear All,
I have a correlation matrix say 'M' (4000x4000) for 4000 genes and I want to
subset it to 'N' (190x190) for 190 genes.
The list of those 190 genes are in variable 't'. So the idea is to read the
names of genes from variable 't' and subset the matrix M accordingly.
Any thoughts are welcome!
Best
Lee
Hi,
Assuming the correlation matrix has dimnames, you can do :
x[ rownames(x) %in% t, colnames(x) %in% t ]
Here is a reproducible example, please make sure you provide one next time.
x <- expand.grid( x1 = 1:2, x2 = 1:2, x3 = 1:2, x4 = 1:2 )
y <- cor( x )
t <- c("x1", "x2")
y[ rownames(y) %in% t, colnames(y) %in% t ]
Romain
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