laurent_r

These are some answers to the Week 279, Task 2, of the Perl Weekly Challenge organized by Mohammad S. Anwar.

Spoiler Alert: This weekly challenge deadline is due in a few days from now (on July 28, 2024 at 23:59). This blog post offers some solutions to this challenge. Please don’t read on if you intend to complete the challenge on your own.

Task 2: Split String

You are given a string, $str.

Write a script to split the given string into two containing exactly same number of vowels and return true if you can otherwise false.

Example 1

Input: $str = "perl"
Ouput: false

Example 2

Input: $str = "book"
Ouput: true

Two possible strings "bo" and "ok" containing exactly one vowel each.

Example 3

Input: $str = "good morning"
Ouput: true

Two possible strings "good " and "morning" containing two vowels each or "good m" and "orning" containing two vowels each.

We are asked to say whether the input string can be split into two substrings containing the same number of vowels. This can always be done if the input string contains an even number of vowels, and can never be done if it contains an odd number of vowels. So all we need to do it to count the vowels and return "True" if the count is even, and "False otherwise'.

Split String in Raku

As said above, we want to count the vowels in the input string. We use the comb method (with a regex matching vowels and an ignore-caseadverb) to get the vowels, count them with the elems method and find out whether the count can be evenly divided by 2, using the %% operator. We end up with a one-liner subroutine:

sub split-string ($in) {
    return $in.comb(/:i <[aeiou}]>/).elems %% 2;
}

for "Perl", "book", "bOok", "good morning" -> $test {
    printf "%-15s => ", $test;
    say split-string $test;
}

This program displays the following output:

$ raku ./split-string.raku
Perl            => False
book            => True
bOok            => True
good morning    => True

Split String in Perl

This is a port to Perl of the above Raku program. Not much to say about this port, except that we return "true" or "false" as strings.

use strict;
use warnings;
use feature 'say';

sub split_string {
    my @vowels = grep {/[aeiou]/i} split "", shift;
    scalar @vowels % 2 == 0 ? "true" : "false";

}

for my $test ("Perl", "book", "bOok", "good morning") {
    printf "%-12s => ", $test;
    say split_string $test;
}

This program displays the following output:_

$ perl ./split-string.pl
Perl         => false
book         => true
bOok         => true
good morning => true

Wrapping up

The next week Perl Weekly Challenge will start soon. If you want to participate in this challenge, please check https://perlweeklychallenge.org/ and make sure you answer the challenge before 23:59 BST (British summer time) on August 4, 2024. And, please, also spread the word about the Perl Weekly Challenge if you can.