[R] length with missing values

[Achim Zeileis]

On Fri, 15 Oct 2004, Luis Rideau Cruz wrote:

> R-help
>
> I have a martix with missing values( in which I want the sample size by
> column)
> When I :
>
> apply(matrix,2,length)
>
> I get the length of the vector regardless of missing values.
> I can't pass an argument to length in apply.
>
> Alternatively I could
>
> ifelse ( is.na ( matrix [, "columns in matrix " ] ) , 0 , 1)
>
> Is there any easier way?

You could omit the missing values before:
  apply(matrix, 2, function(y) length(na.omit(y)))

hth,
Z

> Thank you
>
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