use strict;
my $str = '0.00,-0.00,00.00,-00.00,40.00,-40.00,4.0,-4.0,4.01,-4.01,04.01,-04.01,004.04,-004.04,0004.040,-0004.040,101,.40,-.40,0.40,-0.40
';
my $regex = qr/-?0+\.(0)+\b|\.0+\b|\b0+(?=\.\d*[1-9])|\b0+(?=[1-9]\d*\.)|(\.\d*?)0+\b/p;
my $subst = '$1$2';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html