GNU APL:
(⊂'myfile')≡¨⊂'myfile'
1
(⊂'myfile')≡¨,⊂'myfile'
0
IBM APL 2 returns 1 in both cases. I had a vector I was using. I got one result when I had 2 or more elements, and another result when there was only one element - even though it was still a vector. IBM's result is consistent regardless of 0, 1, 2 or more elements.
Thanks.
Blake