reverse_vowels('Weekly Challenge') eq 'Weekly Challenge': Weekly Challenge #254
Welcome to Weekly Challenge #254! 254, the product of 2 and 127, is a semiprime number. It is deficient, in that the sum of its divisors is 130, which is less than itself.
254 is also the area code for Waco, Texas.
Task 1: Three Power
Submitted by: Mohammad S Anwar
You are given a positive integer,$n.Write a script to return true if the given integer is a power of three otherwise return false.
Let’s Talk About It
So, cube roots are easy. $n ** 3 gets you the cube, and $n ** 1/3 gets you the cube root.
But it isn’t that simple, because everything is a power of three if you get beyond whole numbers. And that’s the core of my test. $n == int $n. If we cast as an integer, wiping away the floating point, are they still equal?
Show Me The Code!
#!/usr/bin/env perl
use strict;
use warnings;
use experimental qw{ say postderef signatures state };
my @examples = ( 27, 0, 6 );
for my $example (@examples) {
my $output = three_power($example);
say $output;
say <<~"END";
Input: \$n = $example
Output: $output
END
}
sub three_power ($input) {
my $cuberoot= $input ** (1/3);
return ( $cuberoot == int $cuberoot ) ? 'true' : 'false';
}
$ ./ch-1.pl
true
Input: $n = 27
Output: true
true
Input: $n = 0
Output: true
false
Input: $n = 6
Output: false
Task 2: Reverse Vowels
Submitted by: Mohammad S Anwar
You are given a string,$s.Write a script to reverse all the vowels (a, e, i, o, u) in the given string.
Let’s Talk About It
We’ll want a list of all the vowels in the string, so we’ll break apart the string (split //, $string), collect the vowels ( grep {/[aeiou]/mix}), make them all lowercase for convenience (map {lc}) and reverse them, so they’re in the right order when we start to replace.
Which we do with substr, which works as both an lvalue (substr($string,1,1) = $char) and an rvalue ($char = substr($string,1,1)). We loop through an index value for all characters, testing if it’s a vowel (again with /[aeiou]/mix), converting to the case of the letter it replaces ($n = uc $n if $c eq uc $c), then replacing (substr( $string, $i, 1 ) = $n).
I’ll point out that both Perl from the examples and weekly challenge come out the same, because their vowels are palindromic: e and eeaee and the case may be, so e replaced e. They’re totally different es, I swear.
Show Me The Code!
#!/usr/bin/env perl
use strict;
use warnings;
use experimental qw{ say postderef signatures state };
use List::Util qw{ max sum0 };
my @examples = ( "Raku", "Perl", "Julia", "Uiua", "Dave", 'signatures', 'weekly challenge' );
for my $example (@examples) {
my $output = reverse_vowels($example);
say <<~"END";
Input: \$s = "$example"
Output: "$output"
END
}
sub reverse_vowels ($string) {
my @vowels =
reverse
map { lc }
grep { /[aeiou]/mix }
split //, $string;
for my $i ( 0 .. -1 + length $string ) {
my $c = substr( $string, $i, 1 );
my $v = $c =~ /[aeiou]/mix ? 1 : 0;
if ( $c =~ /[aeiou]/mix ) {
my $n = shift @vowels;
$n = uc $n if $c eq uc $c;
substr( $string, $i, 1 ) = $n;
}
}
return $string;
}
$ ./ch-2.pl
Input: $s = "Raku"
Output: "Ruka"
Input: $s = "Perl"
Output: "Perl"
Input: $s = "Julia"
Output: "Jaliu"
Input: $s = "Uiua"
Output: "Auiu"
Input: $s = "Dave"
Output: "Deva"
Input: $s = "signatures"
Output: "segnutaris"
Input: $s = "weekly challenge"
Output: "weekly challenge"