Perl: Good way to test if a value is in an array?

Question

If I have an array:

@int_array = (7,101,80,22,42);

How can I check if the integer value 80 is in the array without looping through every element?

Answer 1

You can't without looping. That's part of what it means to be an array. You can use an implicit loop using grep or smartmatch, but there's still a loop. If you want to avoid the loop, use a hash instead (or in addition).

# grep
if ( grep $_ == 80, @int_array ) ...

# smartmatch
use 5.010001;
if ( 80 ~~ @int_array ) ...

Before using smartmatch, note:

http://search.cpan.org/dist/perl-5.18.0/pod/perldelta.pod#The_smartmatch_family_of_features_are_now_experimental:

The smartmatch family of features are now experimental

Smart match, added in v5.10.0 and significantly revised in v5.10.1, has been a regular point of complaint. Although there are a number of ways in which it is useful, it has also proven problematic and confusing for both users and implementors of Perl. There have been a number of proposals on how to best address the problem. It is clear that smartmatch is almost certainly either going to change or go away in the future. Relying on its current behavior is not recommended.

Warnings will now be issued when the parser sees ~~, given, or when. To disable these warnings, you can add this line to the appropriate scope