Dear Monks, I am having difficulties in pruning some empty array references from a nested array. I have tried several strategies with no success. Here below I am going to paste some examples of my trials. It seems to me that the problems here are two: how to check the references for emptiness and how to delete them if they are empty. Thank you in advance. Best regards Luca 
use Data::Dumper;
use feature "say";
no strict;
no warnings;
use Scalar::Util 'reftype';
use Array::DeepUtils qw/:all/;

sub prune1
{ 
    my $count = 0;
    my @arr = @{ $_[0] };
    my $counter = 0;
    foreach ( @arr ) 
    {   
        if ( ref ( $_ ) ) 
        {   
            if ( not ( @{ $_[0] } ) )
            {
                delete ( $arr[$counter] );
            }
            else
            {
                prune1( $_ );
            }
            $counter++;
        }
    }
    return ( \@{$_[0]} );
}

sub prune2
{
    my $node  = $_[0];
    if ( ref( $node ) ) 
    {
        for ( my $i = $#$node; $i >= 0; $i-- ) 
        {
            my $subnode = $node->[$i];
            if ( ref( $subnode ) and ( @$subnode == 0 ) )
            { 
                delete $node->[$i]; 
            }
            else
            {
                prune2( $subnode );
            }
        }
    }
    return ( $_[0] );
}

sub prune3
{
    my ( $node )  = @_;
    my $type = reftype $node // '';
    if ( $type eq 'ARRAY' ) 
    {
        for ( my $i = $#$node; $i >= 0; $i-- ) 
        {
            my $subnode = $node->[$i];
            my $subtype = reftype( $subnode ) // '';
            if ( ( $subtype eq 'ARRAY' ) and ( @$subnode == 0 ) )
            { 
                delete $node->[$i]; 
            }
            else
            {
                prune3( $subnode );
            }
        }
    }
    return ( $_[0] );
}

sub prune4
{
    my ( $arref ) = @_;
    my @arr1 = @$arref;
    my @basket1;
    my $counter1 = 0;
    foreach my $ref1 ( @arr1 ) 
    {
        my @elts1 = @$ref1; 
        my @basket2;
        my $counter2 = 0;
        foreach my $ref2 ( @elts1 ) 
        {
            my @elts2 = @$ref2; 
            my @basket3;
            my $counter3 = 0;
            foreach my $ref3 ( @elts2 ) 
            {
                my @elts3 = @$ref3; 
                my @basket4;
                unless ( ( @elts3 == undef ) or ( @elts3 == () ) or ( 
+@{ $ref3->[$counter3] } ) ) 
                {
                    push ( @basket3, [ @basket4, $ref3 ] );
                } 
                $counter3++;
            }
            unless ( ( @elts2 == undef ) or ( @elts2 == () ) or ( @{ $
+ref2->[$counter2] } ) )
            {
                push ( @basket2, [ @basket3, $ref2 ] );
            }
            $counter2++;
        }
        unless ( ( @elts1 == undef ) or ( @elts1 == () ) or ( @{ $ref1
+->[$counter1] } ) )
        {
            push ( @basket1, [ @basket2, $ref1 ] );
        }
        $counter1++;
    }
    return ( \@basket1 );
}

sub prune5
{     # USING Array::Deeputils
    my $node  = $_[0];
    purge( $node, [] );
    purge( $node, '[]' );
    purge( $node, "" );
    return ( $node );
}

my @a = ( 1, 2, [], 4, [ 11, 22, [], 44 ] );

my $resultref = prune1( \@a ); my @result = @$resultref;
#my $resultref = prune2( \@a ); my @result = @$resultref;
#my $resultref = prune3( \@a ); my @result = @$resultref;
#my $resultref = prune4( \@a ); my @result = @$resultref;
#my $resultref = prune5( \@a ); my @result = @$resultref;

say "result: " . Dumper( @result );

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In reply to pruning of empty arrayrefs in nested array by building_arch

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