kiat has asked for the wisdom of the Perl Monks concerning the following question:

Hi monks,

In the following regex, I'm trying to escape the single quote mark in words with an apostrophe 's': 

my $string = qq~'tom's is silly','some','peter said it's okay'~;

$string =~ s/(?!,)'s/\\'s/g;

print "$string\n";

#output: 'tom\'s silly',\'some','peter said it\'s okay'

#desired output: 'tom\'s is silly','some','peter said it\'s okay'

# In the desired output, the single quote before "some" is not escaped

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The text in $string is the dumped output from MySQL. $string contains the 3 values (1) "tom's silly" (2) "some" and (3) "peter said it's okay"

I need to escape the single quote mark in "tom's" and "it's". My regex escapes the single quote before "some" as well, which is wrong.

Please enlighten me.

Thanks in advance :)

Replies are listed 'Best First'.
Re: Escape single quote marks in words
by runrig (Abbot) on May 27, 2004 at 16:39 UTC
    You want a negative look-behind assertion (?<!...), not a look-ahead.
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[d/l]
      Thanks, runrig!

      It works now :)

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Re: Escape single quote marks in words
by hv (Prior) on May 27, 2004 at 17:00 UTC

    The easiest way to think of this may be:

      replace ' with \' if it lies between two letters

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    .. which you can do like this:
      s/(?>=\w)'(?=\w)/\\'/g;

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    .. or like this:
      s/\b'\b/\\'/g;

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    Hugo

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[d/l]
[select]
      Thanks, Hugo!

      Your regex is more precise and less prone to errors than the one I've, which uses a comma as the context.

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