Since print expects an array, reverse assumes you want to reverse an array, consisting of one value. This is so you can print reverse('M','o','n','k','s');

The solution is to convince reverse you want a scalar, not an array. There are many ways to do this:

# 1. Assign it to a scalar:
$a=reverse("monks");

# 2. Use the keyword "scalar":
print scalar reverse("monks");

# 3. Use some kind of scalar-based manipulation
print reverse("monks")."\n";

# 3a: do almost the same:
print reverse("monks")."";

# 3b: (reverses 100 to 001, then adds 1, printing "2".
print reverse(100)+1;
[download]