my %hash = qw(
       $bar => 1
       $baz => 1
       $boo => 1
);
print "yep!\n" if exists $hash{$foo};
[download]

Regex Solution
timethis 100000: 18 wallclock secs ( 0.41 usr +  0.05 sys =  0.45 CPU)

Hash Solution
timethis 100000:  1 wallclock secs ( 1.58 usr +  0.00 sys =  1.58 CPU)
[download]

Maybe you want to score points for obfuscation:

if ({map{$_=>1}($bar,$baz,$boo)}->{$foo})
{
        print "Yes!\n";
}
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A dirty, and almost as quick way is:

if (grep{$_ eq $foo} $bar, $baz, $boo)
# ...
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If you are comparing frequently, you might want to have a persistent hash which you can refer to on a regular basis. Why create it every time if it is the same?

use Quantum::Superpositions;
use strict;

if ($foo eq any( $bar, $baz, $boo )) {
    print "Yep!";
}
[download]

While that's very easy, it's not as fast as using a comparison operator such as 'eq' or '=='. However using these often leads to redundant and cumbersome looking code:

my @values= qw(foo bar baz bax);
my $test = "foo";
print "woo\n" if (grep {$_ eq $test}@values) ;
[download]

use Switch;

switch ($foo) {
  case [$bar,$baz,$boo] { print "yep!\n" }
}
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buckaduck

If you're truly concerned about speed, use a /o modifier to compile the regex once, rather than re-interpolating the variable each time the regex is fired.

You'll also need to fix the regex to avoid false positives. Here's how I do it:

  my $re = "\A(?:"
         . join("|", $foo, $bar, $baz)
         . ")\Z";
  ...
  if ( /$re/o ) { ... }
[download]

PrimeLord's hash suggestion is quite good. I'd suggest also maybe a for loop as something more traditional:

for( qw( foo bar baz ) ){

    print "yep" and last if $test eq $_;
}
[download]

print "yep" and last if $test eq $_ for( qw( foo bar baz ) );
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do { print "yep"; last; } if $test eq $_ for( qw( foo bar baz ) );
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#!/usr/bin/perl

sub matches(&;@) {
    my $coderef = shift ;
    my @data = @_;
    for  (my $i=0; $i <=  $#data; $i++ ){
        $_ = $data[$i];
        if (&$coderef){
            return wantarray ?  ($_ ,($i  ) ) : $_;
        }
    }
    
    return;         
 }


my @actions = qw(get fetch store info print);

if (my ($v,$i) = matches { $action eq $_ } @actions ){
    print "Found $v at $i\n";
}
# Or
if (my $v = matches { $action eq $_ } @actions ){
    print "Found $v $i\n";
}
# Or
die "Damn! Invalid action $action" unless matches{$action eq $_ } @act
+ions;
[download]

my $code = "sub check { my \$val = shift; if (";
$code .= join (' or ', map { "\$val eq \"$_\""; } (@ceck_vals));
$code .= ") { return 1; } else { return 0; } }";
eval $code;
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my %check = map { $_ => 1; } (@ceck_vals);
if ($check{$val}) { do_foo (); }
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if (grep { $val eq $_ } (@check_vals)) { do_foo (); }
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my $regex = join ('|', @check_vals);
if ($val =~ m/$re/) { do_foo (); }
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use Meta::Ds::Hash;
my($hash)=Meta::Ds::Hash->new();
$hash->insert($bar);
$hash->insert($baz);
$hash->insert($boo);
# later
if($hash->has($foo)) {
  print "Found it\n";
}
[download]

HTH, --traveler

i don't know how to reply to the whole thread so i have used the last answer, sorry for that. if ($foo=~/$bar|$baz|$boo/){ is not strictly equivalent to if (($foo eq $bar) || ($foo eq $baz) || ($foo eq $boo)){ as =~ will be true for $foo=abc and $boo=ab but "abc" will not be eq to "ab" if you want them to be strictly equivalent then it will be something like : if ($foo=~/^$bar$|^$baz$|^$boo$/){ i have tested with string values but not with $var so maybe there is some \ to use at the good places for this to work regards.