Reversing an Array

Problem

You want to reverse an array.

Solution

Use the reverse function:

# reverse @ARRAY into @REVERSED @REVERSED = reverse @ARRAY;

Or use a for loop:

for ($i = $#ARRAY; $i >= 0; $i--) {
 # do something with $ARRAY[$i] }

Discussion

The reverse function actually reverses a list; the for loop simply processes the list in reverse order. If you don't need a reversed copy of the list, for saves memory and time.

If you're using reverse to reverse a list that you just sorted, you should have sorted it in the correct order to begin with. For example:

# two-step: sort then reverse @ascending = sort {
 $a cmp $b
}
@users; @descending = reverse @ascending; # one-step: sort with reverse comparison @descending = sort {
 $b cmp $a
}
@users;

See Also

The reverse function in perlfunc (1) and of Perl Developing; we use reverse in