Dear Monks

if I will to delete the certain element of an array I could do the following:

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

use List::MoreUtils qw(first_index);

my @array = ( 10, 15, 20, 25, 30, 20 );
my $test = 25;

purge_this_one( \@array, $test );
print "@array\n";

sub purge_this_one
{
    my $idx = first_index { $_ == $_[1] } @{$_[0]};
        return @{$_[0]} if $idx == -1; # added (s.Update)
    splice( @{$_[0]}, $idx, 1 ); 
    return @{$_[0]};
}

[download]

Now I try to perform the same thing in an object whose elements are another objects. As a very simple-level Perl programmer I failed miserably and I would be very grateful for your help.

Here is the code (minimal working example) with comments in the problem part:

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

package Person;
use Moose;
use constant DURATION => 100;
has use_duration => ( isa => 'Int', is => 'ro', default => 1);
has frequency => ( isa => 'Int', is => 'ro', default => 50 );
has population => ( 
    handles => {obtain => 'push', 
                    release => 'shift', 
                    inventory => 'count',
               find => 'first_index', 
                    purge => 'delete'},
    isa => 'ArrayRef[Person]',
    default => sub{ [] },
    traits => ['Array'],
    is => 'ro',
);
has number => ( isa => 'Int', is => 'rw', default => 0);
sub need_to_go
{
    my $self = shift;
    return ( rand(DURATION)+1 <= $self->frequency) ? 1 : 0;
}

no Moose;

package main;
use Data::Dumper;
my $people_nr = 25;
my $people = Person->new;

for my $case ( 1 .. $people_nr )
{
    my $per = Person->new;
    $per->number( $case );
    $people->obtain( $per );
}

for my $p ( @{ $people->population } )
{
    if ($p->need_to_go)
    {
            # My problem is here.
            # I suppose to use 
            # first_index( sub { ... }) method
            # and then delete or splice
            # but I cannot figure out what to feed
            # the sub { ... } with
        }
}

print Dumper $people;

[download]

Thank you in advance!

VE

Update: Improved the subroutine purge_this_one by adding the line  return @{$_[0]} if $idx == -1; after comment from locked_user sundialsvc4

In reply to How to remove the certain element of an object by vagabonding electron

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