Your code looks fine. The slashes will not interfere with forming hash keys.

The problem appears to be that the trailing data is making each element of @array unique. If there is no way of distinguishing where a path ends and data starts, you have an intractable problem. Ideally, the data should start with ASCII NUL, which cannot be part of a file name. Then,

my %saw;
@out = grep {!$saw{$_}++}
       map  {substr $_, 0, index($_,"\0")}
       @array;
[download]

If you don't have that luxury, can you characterize what the filename extensions are? Matching those can locate the end of the path for you.