[R] ifelse problem

[Uwe Ligges]

Adrian DUSA wrote:

> Dear all,
> 
> There is something I'm missing in order to understand the following behavior:
> 
> 
>>aa <- c("test", "name")
>>ifelse(any(nchar(aa) < 3), aa[-which(nchar(aa) < 3)], aa)
 > [1] "test"
> 
>>any(nchar(aa) < 3)
> 
> [1] FALSE
> 
> Shouldn't the ifelse function return the whole aa vector?

No, ifelse() works vetorized, see ?ifelse. You do not want such a behaviour.

In fact, you do not want "if" in any combination with "else", but:

   aa[!(nchar(aa) < 3)]

Uwe Ligges



> Using if and else separately, I get the correct result...
> 
> 
>>if (any(nchar(aa) < 3)) {
> 
>          aa[-which(nchar(aa) < 3)]
>          } else {
>          aa
>          }
> [1] "test" "name"
> 
> 
> Thanks in advance,
> Adrian
>