in reply to Quarms with RegEx

I think the line:
if ($curline !~ /^#\s/ or $curline !~ /^\s/)

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is wrong.

You almost never want two negative conditions combined with 'or'.

Try 'and' between the conditions:

if ($curline !~ /^#\s/ and $curline !~ /^\s/)

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Re: Re: Quarms with RegEx
by blakem (Monsignor) on Aug 28, 2001 at 12:53 UTC
    nice catch wise monk 
    if ($curline !~ /^#\s/ or $curline !~ /^\s/)

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    is logically equivalent to: 
    if (1)

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    because every string will either A.) not start with a '#' or B.) not start with a space.

    Might I recommend a smarter regex rather than anding two simple ones together? 

    if ($curline !~ /^#?\s/)

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    -Blake

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      if ($curline !~ /^#?\s/)

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      That will not work, because a domain line looks like:
      #domain1

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      And that will not match your regex, so the condition is true, which is wrong.
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        Ok, what am I missing here.... 
        #!/usr/bin/perl -w
use strict;

for ('#abc',' abc','abc','# abc',' #abc') {
  my $v1 = ($_ !~ /^#\s/ and $_ !~ /^\s/) || 0;  # yours
  my $v2 = ($_ !~ /^#?\s/) || 0;                 # mine
  print "$v1 $v2 '$_'\n";
}

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        Output: 
        1 1 '#abc'
0 0 ' abc'
1 1 'abc'
0 0 '# abc'
0 0 ' #abc'

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        -Blake

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Re: Re: Quarms with RegEx
by stefan k (Curate) on Aug 28, 2001 at 12:47 UTC
    just because the phone rang while I was in the process of writing ... :)
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