APM: Regular Expression Question

[Tim Peoples]

I think what you're looking for is something like this:

    $cnt = 6;
    $piece =~ s/(?<!\")\t/\"\t\"/ while $cnt--;

This will substitute the first six tabs with quoted tabs.  The (?<!\") 
business is a "/zero-width negative look-behind assertion/" that says it 
should only match tab chars that are not immediately preceded by a quote 
char (but the quote char is not included in the text to get 
substituted).  since there is no /g modifier on the substitution, we 
have to do it all with an in-line while loop constrained by $cnt.

Tim.

Barron Snyder (CE CEN) wrote:
>
> $piece =~ s/\t/\"\t\"/g;
>
>  
>
> With the above code I'm searching for all tab characters and replacing 
> them with a tab surrounded by double-quotes. Is there a way without 
> putting this in a coding loop, to replace say, only the first three 
> instances it finds in $piece? It seems like a nice way to do this 
> would to be able to replace the "g" with an integer indicating how 
> many replacements to do but it doesn't seem to work like that <grin>.
>
>  
>
> I'm parsing some columnar data (7 columns) and I want to put 
> double-quotes around the first six columns. I've figured out a way to 
> do it but it's kind of clumsy. I thought you experts may be able to 
> show a Perl newbie a more elegant way to do it.
>
>  
>
> Thanks,
>
>  
>
> Barron Snyder
>
> Software Development, Financial Systems Team
>
> *Whole Foods Market, HQ*
>
> barron.snyder at wholefoods.com <mailto:barron.snyder at wholefoods.com>
>
>  
>
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-- 
 _______________________________________________________________________
                                                      Timothy E. Peoples
                                                   Have Camel, Will Code
                                                         tim at toolman.org




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