What is the proper way to check if a string is empty in Perl?

Solution 1:

For string comparisons in Perl, use eq or ne:

if ($str eq "")
{
  // ...
}

The == and != operators are numeric comparison operators. They will attempt to convert both operands to integers before comparing them.

See the perlop man page for more information.

Solution 2:

1. Due to the way that strings are stored in Perl, getting the length of a string is optimized.
   if (length $str) is a good way of checking that a string is non-empty.

2. If you're in a situation where you haven't already guarded against undef, then the catch-all for "non-empty" that won't warn is if (defined $str and length $str).