How to Remove Items from Set based on a Condition in Perl - Step by Step Examples

How to Remove Items from Set based on a Condition in Perl ?

Answer

To remove items from a set (represented as a hash) based on a condition in Perl, you can iterate over the hash and delete items that meet the condition.

✐ Examples

1 Remove Even Numbers from a Set

In this example,

First, we create a hash named %number_set to represent the set, with integer keys and values both set to 1: my %number_set = (1 => 1, 2 => 1, 3 => 1, 4 => 1, 5 => 1);.
Next, we use a foreach loop to iterate over the keys of the hash.
Within the loop, we check if the current key (number) is even using the modulus operator %.
If the number is even, we delete it from the hash using the delete function.
We print the updated hash to verify that even numbers have been removed.

Perl Program

use strict;
use warnings;

my %number_set = (1 => 1, 2 => 1, 3 => 1, 4 => 1, 5 => 1);
print "Original Set: ";
print join(", ", keys %number_set) . "\n";

foreach my $num (keys %number_set) {
    if ($num % 2 == 0) {
        delete $number_set{$num};
    }
}

print "Set after removing even numbers: ";
print join(", ", keys %number_set) . "\n";

Output

Original Set: 1, 2, 3, 4, 5
Set after removing even numbers: 1, 3, 5

2 Remove Strings Longer Than 4 Characters from a Set

In this example,

First, we create a hash named %string_set to represent the set, with string keys and values both set to 1: my %string_set = ("apple" => 1, "banana" => 1, "orange" => 1, "kiwi" => 1);.
Next, we use a foreach loop to iterate over the keys of the hash.
Within the loop, we check if the length of the current key (string) is greater than 4 using the length function.
If the length is greater than 4, we delete the string from the hash using the delete function.
We print the updated hash to verify that strings longer than 4 characters have been removed.

Perl Program

use strict;
use warnings;

my %string_set = ("apple" => 1, "banana" => 1, "orange" => 1, "kiwi" => 1);
print "Original Set: ";
print join(", ", keys %string_set) . "\n";

foreach my $str (keys %string_set) {
    if (length($str) > 4) {
        delete $string_set{$str};
    }
}

print "Set after removing strings longer than 4 characters: ";
print join(", ", keys %string_set) . "\n";

Output

Original Set: apple, banana, orange, kiwi
Set after removing strings longer than 4 characters: kiwi

Summary

In this tutorial, we learned How to Remove Items from Set based on a Condition in Perl language with well detailed examples.

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