# [R] Find solution for an error in the condition of if

Duncan Murdoch murdoch.duncan at gmail.com
Fri Apr 30 11:20:15 CEST 2010

```On 30/04/2010 4:19 AM, anderson nuel wrote:
> Dear r-help,
>
> Could you help me to find a solution for this error:
>
> Il y a eu 50 avis ou plus (utilisez warnings() pour voir les 50 premiers)
>
>
>> warnings()
>>
> Messages d'avis :
> 1: In if ((data[pa, k] == df[, j]) & (data[ch, k] == i)) { ... :
>   la condition a une longueur > 1 et seul le premier élément est utilisé
>

It's saying that the condition has length > 1 and only the first element
is used.  This is probably coming from the first part of the test:
data[pa,k] will be scalar, but df[,j] looks like a vector of every
element in column j.  The result is a vector with as many entries as you
have rows in df.  Only the first of them will be compared to data[pa, k].

Duncan Murdoch
> 2: In if ((data[pa, k] == df[, j]) & (data[ch, k] == i)) { ... :
>   la condition a une longueur > 1 et seul le premier élément est utilisé
>
>
> ch=3
> pa=c(1,2)
> r=2
> t=4
> nb=15
> ni=array(0,c( r,t))
>
> for ( i  in 1:r){
>
> for (j in 1:t ){
>
>     for (k in 1:nb){
>
>         if ( (data[pa,k]== df[,j]) & (data[ch,k]==i)){
>
>             ni[i,j]=ni[i,j]+1
>         }
>     }
> }
> }
>
> Best  Regards
>
> 	[[alternative HTML version deleted]]
>
>
> ------------------------------------------------------------------------
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

```