NAME
List::Helpers::XS - Perl extension to provide some usefull functions with arrays
SYNOPSIS
use List::Helpers::XS qw/ :shuffle :slice /;
my $slice = random_slice(\@list, $size); # returns array reference
random_slice_void(\@list, $size);
shuffle(\@list);
shuffle(@list);
# undef value will be skipped
shuffle_multi(\@list1, \@list2, undef, \@list3);
# the same for tied arrays
tie(@list, "MyPackage");
shuffle(@list);
shuffle(\@list);
random_slice_void(\@list, $size);
my $slice = random_slice(\@list, $size); # returns array referenceDESCRIPTION
This module provides some rare but usefull functions to work with arrays. It supports tied arrays.
random_slice
This method receives the array and the amount of required elements to be shuffled, shuffles array's elements and returns the array reference to the new arrays with num elements from original one.
If num is equal or higher than amount of elements in array, then it won't do any work.
It doesn't shuffle the whole array, it shuffles only num elements and returns only them. So, if you need to shuffle and get back only a part of array, then this method can be faster than others approaches.
Be aware that the original array will be shuffled too, but it won't be sliced.
random_slice_void
This method receives the array and the amount of required elements to be shuffled, shuffles array's elements. Doesn't return anything.
After method being called the passed array will contain only random num elements from the original array.
This method is a memory efficient, but it can a bit slow down in case of huge arrays and num.
In this case please consider the usage of random_slice method.
shuflle
Shuffles the provided array. Doesn't return anything.
shuffle_multi
Shuffles multiple arrays. Each array must be passed as array reference. All undefined arrays will be skipped. This method will allow you to save some time by getting rid of extra calls. You can pass so many arguments as Perl stack allows.
Benchmarks
Below you can find some benchmarks of random_slice and random_slice_void methods in comparison with Array::Shuffle::shuffle_array / Array::Shuffle::shuffle_huge_array with splice method invocation afterwards.
Total amount of elements in initial array: 250
shuffle_array and splice random_slice random_slice_void
shuffle_array and splice -- -45% -52%
random_slice 82% -- -12%
random_slice_void 107% 14% --Total amount of elements in initial array: 25_000
shuffle_array and splice random_slice_void random_slice
shuffle_array and splice -- -51% -56%
random_slice_void 106% -- -9%
random_slice 126% 10% --Total amount of elements in initial array: 250_000
shuffle_array and splice random_slice_void random_slice
shuffle_array and splice -- -63% -67%
random_slice_void 172% -- -9%
random_slice 200% 10% --The benchmark code is below:
cmpthese (
1_000_000,
{
'shuffle_array and splice' => sub {
my $arr = [@array];
if ($slice_size < scalar $arr->@*) {
shuffle_array(@$arr);
$arr = [splice(@$arr, 0, $slice_size)];
}
},
'random_slice' => sub {
my $arr = [@array];
$arr = random_slice($arr, $slice_size);
},
'random_slice_void' => sub {
my $arr = [@array];
random_slice_void($arr, $slice_size);
},
}
);The benchmark results for shuffle method
shuffle_huge_array List::Helpers::XS::shuffle
shuffle_huge_array -- -5%
List::Helpers::XS::shuffle 5% --
shuffle_array List::Helpers::XS::shuffle
shuffle_array -- -4%
List::Helpers::XS::shuffle 4% --
List::Util::shuffle List::Helpers::XS::shuffle
List::Util::shuffle -- -63%
List::Helpers::XS::shuffle 170% --AUTHOR
Chernenko Dmitriy, cdn@cpan.org
COPYRIGHT AND LICENSE
Copyright (C) 2021 by Dmitriy
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.26.1 or, at your option, any later version of Perl 5 you may have available.