[R] Remove levels

[Peter Dalgaard]

Marc Bernard <bernarduse1 at yahoo.fr> writes:

> Daer All,
>  
> I have a factor  variable, X with 5 levels. When I type tables(X) it gives me:
>  
> table(X)
> 1     2   3    4   5 
> 10   5    0   0   0
>  
> How to drop the levels with zeros such that when I will type:
> table(X) it will give me:
>  
> table(X)
> 1     2   
> 10   5    

table(factor(X)) or table(X[drop=TRUE]) should do it. The latter runs
the former, but the intention might be clearer.

-- 
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