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How can I check if a value is undef in Perl?

Best asked by an example:

my $var1=1;
my $var2;
my $var3=3;

# say "at least one undef" if at least one of $var1, $var2, $var3 is undef

Obviously I can explicitly loop and do that, but I always like to find one liners that achieve the same result.

Solution 
  • if (grep { !defined } $var1, $var2, $var3) {
  say 'at least one undef'
}

    one liner

    say 'at least one undef' if grep { !defined } $var1, $var2, $var3;