How can I filter an array without using a loop in Perl?

Question

Here I am trying to filter only the elements that do not have a substring world and store the results back to the same array. What is the correct way to do this

Answer 1

Use grep:

sub remove_worlds { grep !/world/, @_ }

For example:

@arrf = remove_worlds @arr;

Using grep is the most natural fit for your particular problem, but for completeness, you can also do it with map:

sub remove_worlds { map /world/ ? () : $_, @_ }

It's a bit klunky here, but map gives you a hook in case you want to process the filtered elements before discarding them.

Answer 2

Use grep

@no_world_for_tomorrow = grep { !/world/ } @feathers;

For details, perldoc -f grep.

Answer 3

You can use the grep function as:

@arrf =  grep(!/world/, @arr);

The expression !/world/ is evaluated for each element of the array @arr and a list of elements which which the expression evaluated to be true is returned.

The expression /world/ searches for the word world and is true it's present. And the expression !/world/ is true if the string world is absent.

Answer 4

That would be grep():

#!/usr/bin/perl

use strict;
use warnings;

my @arr = ('hello 1', 'hello 2', 'hello 3', 'world1', 'hello 4', 'world2');
my @narr = ( );

print "@arr\n";
@narr = grep(!/world/, @arr);
print "@narr\n";