[R] compute variance of every column in a matrix without a loop

[Jonathan Baron]

On 03/16/02 19:43, Francisco J Molina wrote:
>Is it possible to compute the variance of every column in a matrix
>without a loop?

If the matrix is m1,

apply(m1,2,var)

or, with missing data,

apply(m1,2,var,na.rm=T)

In general, apply() and related functions are well worth
understanding.
-- 
Jonathan Baron, Professor of Psychology, University of Pennsylvania
Home page: http://www.sas.upenn.edu/~baron
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