Solution To Reddit Daily Programmer #224 - Shuffling A List

shuffle.pl

!/usr/bin/env perl
use warnings;
use strict;

sub shuffle_stuff {
    #Turn the values into an array.
    my $values = shift;
    my @values = split(" ", $values);

    #Figure out length. Create an array of index and a final value array.
    my $length = @values;
    my @holder_array = (0..($length-1));
    my @final_array = (0..($length-1));

    #Make the index array have values that initially match the index.
    for(my $i = 0; $i < $length; $i++) {
        $holder_array[$i] = $i;
    }

    #Shuffle the values to new indexes in the final array.
    foreach my $item(@values) {
        #Redo the length since it'll change after each iteration.
        $length = @holder_array;

        #Make a random number in the bounds of the length.
        my $index = int(rand($length));

        #Assign the current value to a location in the final array.
        $final_array[$holder_array[$index]] = $item;

        #Splice that index value out of the holder array.
        splice(@holder_array, $index, 1);
    }

    #Print the values.
    foreach my $item(@final_array) {
        print "$item ";
    }

    print "\n";
}

#Get the initial input.
my $numbers= "1 2 3 4 5 6 7 8";
my $words= "apple blackberry cherry dragonfruit grapefruit kumquat mango nectarine persimmon raspberry raspberry";
my $letters = "a e i o u";

#Pass them to the function to shuffle.
shuffle_stuff($numbers);
shuffle_stuff($words);
shuffle_stuff($letters);