I have a small array of strings holding zeros(0) as placeholders 
my @p;
my @pos = qw(1 2 3 4);
foreach (@pos) {
    $p[$_] = '0' x 128;
}

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and I want to set the char to one(1) if I have the need to hold that position 
my @ranges = qw(1..4 5..8 9..12 13..16 1..8 9..16 )
foreach my $range ( @ranges ) {
    foreach($range){
        substr($str1,$_,1) = '1';
    }
}

[download]
Thats fine but I need to test if the nums are already set to '1' so I move to a different string that's not set yet i.e., I don't want to clobber an existing range that has a placeholder. That's where I'm stuck. How to test a range of chars in a string to see if the value is '1'. I don't know why I'm stuck. Does this question make sense? Thanks.

In reply to strings as placeholders by Anonymous Monk

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