File Coverage

blib/lib/Array/Sample/SysRand.pm

Criterion	Covered	Total	%
statement	22	22	100.0
branch	6	6	100.0
condition	5	5	100.0
subroutine	5	5	100.0
pod	1	1	100.0
total	39	39	100.0

package Array::Sample::SysRand;

use 5.010001;
use strict;
use warnings;

use Exporter qw(import);

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2022-05-20'; # DATE
our $DIST = 'Array-Sample-SysRand'; # DIST
our $VERSION = '0.003'; # VERSION

our @EXPORT_OK = qw(sample_sysrand);

sub sample_sysrand {
    my ($ary, $n, $opts) = @_;
    $opts //= {};

    return () if $n < 1 || @$ary < 1;

    my $k = @$ary / $n;
    my $idx = rand() * @$ary;

    my @res;
    for my $i (1..$n) {
        push @res, $opts->{pos} ? int($idx) : $ary->[int($idx)];
        $idx += $k;
        $idx -= @$ary if $idx >= @$ary;
    }

    @res;
}

1;
# ABSTRACT: Systematic random sampling from an array

__END__