[R] select data

[David Winsemius]

On May 14, 2012, at 12:32 PM, Andrea Sica wrote:

> Dear all,
>
> I am sure it won't be difficult for you!!
> I need to calculate the average among variables for the single units  
> of my
> dataset.
> But, while doing it, I need to do not consider some values.
> To better explain, think like there are two units and three variables:
>
>      V1    V2     V3
> [1]   3     -2      4
> [2]  -1      4      1
>
> and you want to calculate the average by row, without considering  
> those
> negative values:
>
> => mean(1row) = (3+4)/2
> => mean(2row) = (4+1)/2

perhaps (untested in absence of reproducble example):

apply(dfrm, 1, function(x) mean(x[x>=0]) ) # would also work for a  
matrix object.

>
> Could anyone please give me the commands to do that in R?
>
> Thank you so much
>
> 	[[alternative HTML version deleted]]
>
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David Winsemius, MD
West Hartford, CT