Try regex

sub test
{
    my $str =shift;
    
    if(length($str)==11)
    {
        $str=~ m/^(\d(\d{6})\d+)$/;
        print"$1 $2\n";
    }
    else
    {
        $str=~ m/^((\d{6})\d+)$/;
        print"$1$2 $2\n";
    }
}

my $a='01234567890';
my $b ='15556667777';

test($a);
test($b);

[download]

Output 01234567890 123456
15556667777 555666

In reply to Re^2: Negative Index with "substr" Not Working by grasshopper!!!
in thread Negative Index with "substr" Not Working by he204035

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