Not built-in. There are probably modules (look for Set::* modules on CPAN) that do it. I just use something like: 

sub s_in_a # scalar in array
{
  my $s = shift;
  foreach (@_)
  {
    return 1 if $s eq $_;
  }
  0;
}

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In reply to Re: boolean IN(); function in perl like by Tanktalus
in thread boolean IN(); function in perl like by Frank John

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