[R] Specify a minimum number of valid arguments for the mean function

[Uwe Ligges]

On 13.09.2010 17:43, Luana Marotta wrote:
> Hello all,
>
> I want to specify a minimum number of valid arguments for the mean
> function--I have 5 variables but I want the mean only of cases that have at
> least 3 valid answers. What is the best way to do that?


If your 5 variables are in a data.frame dat:

sapply(dat, function(x) if(sum(!is.na(x)) > 2) mean(x) else NA)

Uwe Ligges


> Thank you very much!
>
> Luana
>
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>
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