[R]:?alternative to loop

[Uwe Ligges]

nicolas baurin wrote:
> for the application of a function to each column of a matrix (ex:
> function sum()), i'd like to know if there is a simpler (and faster)
> alternative to a loop like :
> 
> for (i in 1: ncol(m)){sum(m[i])}

This will not work in any way, I suppose.
If you want to simplify something like
 
 s <- NULL
 for (i in 1: ncol(m)){ s[i] <- sum(m[,i])}

you should try

 s <- apply(m, 2, sum) 


Have a look in documentation to apply(.) !

Regards,
Uwe Ligges
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