[R] question about setdiff()

[Svetlana Eden]

Thank you for your answers,
I have another question:

the behaviour of setdiff(indicesFalse, indicesNA)
does not seem predictable to me.


> indices
[1] 1 2 3 4 5 6
> compareVector
[1]    NA  TRUE  TRUE  TRUE FALSE    NA
>   indicesNA = indices[is.na(compareVector)]
>   indicesNA
[1] 1 6
>   indicesFalse = indices[compareVector == FALSE]
>   indicesFalse
[1] NA  5 NA
>   setdiff(indicesNA, indicesFalse) ######################## OK
[1] 1 6
>   setdiff(indicesFalse, indicesNA) ######################## I would
>   expect here 'NA 5 NA'
[1] NA  5
>


-- 
Svetlana Eden        Biostatistician II            School of Medicine
                     Department of Biostatistics   Vanderbilt University