Re: regex doubt on excluding

[hdb]

A question on whitespace is difficult to address as one cannot see the objects of interest. Your regex suggests that in a multiline string you want to replace lines consisting only of whitespaces with truly empty lines. Whitespaces in non-empty lines will be preserved. I am replacing the whitespace with 'x' to see where we got matches:

use strict;
use warnings;

my $string = "next line is spaces
      
next line is tabs
        
and now some newlines



end";

$string =~ s/^\s*$/x/mg;

print "$string\n";

The result of this would be:

next line is spaces
x
next line is tabs
x
and now some newlines
xx
end

When you say you want to exclude newlines from the match, what is the desired effect you want to see? Preserve multiple empty lines?

[Anonymous Monk]

Yes, that's it, Preserve multiple empty lines. (but without white-spaces)

[hdb]

How about this?

$string =~ s/^\s*?\n$/\n/mg;

UPDATE: the regex is not working properly but this should, the \n and the $ are somewhat duplicate:

$string =~ s/^\s*?\n/\n/mg;

[Anonymous Monk]

Thank you hdb... it worked...

its working with $string =~ s/^\s*?\n/\n/mg; too... :-)