[R] length with missing values

[Dimitris Rizopoulos]

Hi Luis,

just use:

apply( mat, 2, function(x) length(x[!is.na(x)]) )

I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


> ----- Original Message ----- 
> From: "Luis Rideau Cruz" <Luisr at frs.fo>
> To: <r-help at stat.math.ethz.ch>
> Sent: Friday, October 15, 2004 1:01 PM
> Subject: [R] length with missing values
>
>
>> 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?
>>
>> Thank you
>>
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>
>