Re: Zero-suppression Regex

[Dirk Bremer]

Here is a quicker version of the zero-suppression routine that will also float a 
leading sign character:

    sub ZeroSuppress2($)
    {
        my $self = shift;

        # Return if the argument is less than two digits.
        return($self) if (length($self) < 2);

        # Search for a embedded decimal point.
        my $decimal  = rindex($self,'.');

        # If the decimal point exists, substract one from its position
        # to define the end point of the zero-suppression, else determine
        # the entire length of the string and subtract one to define the
        # end point of the zero-suppression.
        if ($decimal > 0) {$decimal-- ;}
        else {$decimal = length($self) - 1;}

        # Iterate through the list suppressing leading zeroes.
        my $i;
        my $c;
        for ($i = 0; $i < $decimal; $i++)
        {
            $c = substr($self,$i,1);
            # Skip to the next character if the current character is a
            # plus-sign, minus-sign, or space.
            next if ($c eq ' ' or
                     $c eq '+' or
                     $c eq '-');

            # Terminate the loop if the current character is s digit.
            last if ($c > 0);

            # Replace the zero in the current character with a space.
            substr($self,$i,1) = ' ';
        }

        $c = substr($self,0,1);
        # Check for a leading sign-character.
        if ($c eq '+' or $c eq '-')
        {
            # If the list has more two elements, move the sign-character
            # from the leftmost position to the position of the rightmost
            # space character.
            if ($i > 1) {substr($self,$i - 1,1) = $c; substr($self,0,1) = ' ';}
        }

        return($self);
    }

After running some more benchmarks, this routine is several orders of magnitude faster 
than sprinf or a regex. 

Dirk Bremer - Systems Programmer II - ESS/AMS  - NISC St. Peters
636-922-9158 ext. 652 fax 636-447-4471

[EMAIL PROTECTED]
www.nisc.cc


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