[R] matrix manipulations
David Andel
andel at ifi.unizh.ch
Tue Jul 15 18:51:43 CEST 2003
Hi
cor(x,apply(x,1,sum)) gives me the correlations of each column with the sums of each row (correct me if I'm wrong, please).
What I need are the correlations of each column with the sums of each row except the entry in the given column. It seems that for any one column i I get it by doing:
cor(x[,i],apply(x[,-i],1,sum))
But I struggle to get it for all the columns. I was trying things like:
for(i in 1:ncol(x)) cor(x[,i],apply(x[,-i],1,sum))
which doesn't generate any output at all, and
> rbind(for(i in 1:ncol(x)) cor(x[,i],apply(x[,-i],1,sum)))
[,1]
[1,] 0.1880237
outputs just the result of the very last column.
I know that it shouldn't be necessary to use for(), but I couldn't figure out a way how to do the task using e.g. apply().
How do you get the results of all columns?
Thank you,
David
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