use strict;
use warnings;

# MATCHES
{
    my $scalar = grep /\d+/, 1 .. 5;
    print "$scalar\n";
}

{
    my ($scalar) = grep /\d+/, 1 .. 5;
    print "$scalar\n";
}

# NO MATCHES
{
    my $scalar = grep /\d+/, 'a' .. 'z';
    print "$scalar\n";
}

{
    my ($scalar) = grep /\d+/, 'a' .. 'z';
    print( (defined $scalar) ? "$scalar\n" : "undefined\n" );
}

__END__

5
1
0
undefined