How can I take n elements at random from a Perl array?

Question

I have an array, A = [a1,a2,a3,...aP] with size P. I have to sample q elements from array A.

I plan to use a loop with q

Answer 1

From perldoc perlfaq4:

How do I shuffle an array randomly?

If you either have Perl 5.8.0 or later installed, or if you have Scalar-List-Utils 1.03 or later installed, you can say:

use List::Util 'shuffle';
@shuffled = shuffle(@list);

If not, you can use a Fisher-Yates shuffle.

sub fisher_yates_shuffle {

    my $deck = shift;  # $deck is a reference to an array
    return unless @$deck; # must not be empty!

    my $i = @$deck;
    while (--$i) {
        my $j = int rand ($i+1);
        @$deck[$i,$j] = @$deck[$j,$i];
    }
}


# shuffle my mpeg collection
# 

my @mpeg = 

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You could also use List::Gen:

my $gen = <1..10>;
print "$_\n" for $gen->pick(5);  # prints five random numbers