Perl tries to make things as easy as possible for you and this is a good example.

In most cases, what you actually want is as simple as:

if ($value) {
  # $value contains something useful
} else {
  # $value is "empty"
}
[download]

(Note that the logic is reversed from your original example)

What we're doing here is checking the "truth" of $value. $value will be "false" if it contains any of the following values:

• "undef" (i.e. if it hasn't been given a value)
• The number 0
• The string "0"
• The empty string ("")

Any other value in $value will evaluate to "true".

This is all you need in most cases. There are a couple of "corner cases" that you sometimes have to consider:

• Sometimes 0 is an acceptable value. You account for that by using if ($value or $value == 0).
• Sonetimes you might want to test that $value contains nothing but whitespace characters. The easiest way to do that is by checking for the presence of non-whitespace characters with if ($value =~ /\S/).

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