[R] Error in using nlevels in apply function

Sébastien pomchip at free.fr
Mon Aug 6 18:10:39 CEST 2007

Dear R users,

I am currently trying to create my first personnal function and use it 
with the apply function. The purpose of this function is to create a 
vector summarizing the number of levels in a given selection of 
data.frame columns.
I tried to transpose the indexation method used by the nlevels function 
but it doesn't seem to work. I did not find anything uesful in the 
archives so could someone point to me where my mistake(s) is (are) ?

Thanks in advance




nelem<-function(x,col.id) nlevels(factor(x[,col.id]))


#The error message is the following
#>Error in x[, col.id] : incorrect number of dimensions

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