Re: comparison with bitwise operators

I can think of 3 ways:

grep
List::MoreUtils::any
a hash

use warnings;
use strict;
use List::MoreUtils qw (any);

my $var = 3;

if (grep { $var == $_ } 2, 3) {
    print "in list\n";
}
else {
    print "not in list\n";
}

if (any { $var == $_ } 2, 3) {
    print "in list\n";
}
else {
    print "not in list\n";
}

my %vals = map {$_ => 1} 2, 3;
if (exists $vals{$var}) {
    print "in list\n";
}
else {
    print "not in list\n";
}

__END__

in list
in list
in list
[download]

Update: a 4th way involves the smart match operator

use 5.010;
if ($var ~~ [2, 3]) {
    print "in list\n";
}
else {
    print "not in list\n";
}
[download]

Comment on Re: comparison with bitwise operators Select or Download Code

Replies are listed 'Best First'.
Re^2: comparison with bitwise operators by LanX (Saint) on Jan 13, 2011 at 22:23 UTC
> `my %vals = map {$_ => 1} 2, 3;` > `if (exists $vals{$var}) {` > `print "in list\n";` > `}` if you wanna test with `exists` hash-slices are shorter! :) `my %vals; @vals{2,3}=();` [download] but need a separate step for declaration! :( UPDATE: why do you check with exists anyway? Cheers Rolf	[reply] [d/l] [select]
Re^3: comparison with bitwise operators by toolic (Bishop) on Jan 14, 2011 at 14:11 UTC
why do you check with exists anyway? Out of habit. I consider it defensive programming. In this small example, there is no need to use exists because I have clearly set the values of all keys to 1, which is defined and true, as opposed to undef or 0. I also kinda like how it reads. If you can convince me there is a significant penalty (performance/memory/etc.) for using exists, then I may consider changing my habit.	[reply]
Re^2: comparison with bitwise operators by alextor (Novice) on Jan 13, 2011 at 22:00 UTC
thanks!	[reply]