There are three potential levels of 'blankness' that you should be checking for.

  1. Variable has never been given a value.
    Test with unless (defined $foo)
  2. Variable contains an empty string.
    Test with if ($foo eq '') (note that you could simplify it to unless ($foo) if you could be sure that zero wasn't a valid value.)
  3. Variable contains only whitespace.
    Test with if ($foo =~ /\S/)

Update Thanks to merlyn for pointing out the error in the second bullet point - which I've now corrected.

--
<http://www.dave.org.uk>

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

In reply to Re: What is the best way to determine if a string is blank? by davorg
in thread What is the best way to determine if a string is blank? by fongsaiyuk

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