Perl: if ( element in list )

Question

I\'m looking for presence of an element in a list.

In Python there is an in keyword and I would do something like:

if element in list:
            


        

Answer 1

List::MoreUtils

On perl >= 5.10 the smart match operator is surely the easiest way, as many others have already said.

On older versions of perl, I would instead suggest List::MoreUtils::any.

List::MoreUtils is not a core module (some say it should be) but it's very popular and it's included in major perl distributions.

It has the following advantages:

• it returns true/false (as Python's in does) and not the value of the element, as List::Util::first does (which makes it hard to test, as noted above);
• unlike grep, it stops at the first element which passes the test (perl's smart match operator short circuits as well);
• it works with any perl version (well, >= 5.00503 at least).

Here is an example which works with any searched (scalar) value, including undef:

use List::MoreUtils qw(any);

my $value = 'test'; # or any other scalar
my @array = (1, 2, undef, 'test', 5, 6);

no warnings 'uninitialized';

if ( any { $_ eq $value } @array ) {
    print "$value present\n"
}

P.S.

(In production code it's better to narrow the scope of no warnings 'uninitialized').