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Re: regex doubt on excluding

by hdb (Monsignor)
on Apr 21, 2014 at 08:40 UTC ( #1082994=note: print w/replies, xml ) Need Help??

in reply to regex doubt on excluding

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?

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Re^2: regex doubt on excluding
by Anonymous Monk on Apr 21, 2014 at 08:44 UTC
    Yes, that's it, Preserve multiple empty lines. (but without white-spaces)

      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;

        Thank you hdb... it worked...

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

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