tst <- apply(my.mat, 2, mean) < 1
... and
rowMeans(my.mat) < 1
will be faster, but perhaps not working for the requested "more complicated query".
Uwe Ligges
my.mat[,tst]
Will return only columns with mean < 1
Jim
James W. MacDonald Affymetrix and cDNA Microarray Core University of Michigan Cancer Center 1500 E. Medical Center Drive 7410 CCGC Ann Arbor MI 48109 734-647-5623
<[EMAIL PROTECTED]> 07/22/03 01:53PM >>>
I have a matrix with some very funky data. I want to drop the columns with a mean > 1 (for instance). #Example: my.mat <- matrix(rnorm(100, 0, 3), nrow = 10)
#I know I can get the row means: apply(my.mat,1, mean)
I think I need to get a vector that has those rows > 1
my.mat[-rows>1,]
The actual querry is much more complicated but this gives an approximation.
Thanks.
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