FAQ: How do I change the Nth occurrence of something? 
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 FAQ: How do I change the Nth occurrence of something?

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+
  How do I change the Nth occurrence of something?

    You have to keep track of N yourself. For example, let's say you want to
    change the fifth occurrence of ""whoever"" or ""whomever"" into
    ""whosoever"" or ""whomsoever"", case insensitively. These all assume
    that $_ contains the string to be altered.

        $count = 0;
        s{((whom?)ever)}{
            ++$count == 5           # is it the 5th?
                ? "${2}soever"      # yes, swap
                : $1                # renege and leave it there
        }ige;

    In the more general case, you can use the "/g" modifier in a "while"
    loop, keeping count of matches.

        $WANT = 3;
        $count = 0;
        $_ = "One fish two fish red fish blue fish";
        while (/(\w+)\s+fish\b/gi) {
            if (++$count == $WANT) {
                print "The third fish is a $1 one.\n";
            }
        }

    That prints out: ""The third fish is a red one."" You can also use a
    repetition count and repeated pattern like this:

        /(?:\w+\s+fish\s+){2}(\w+)\s+fish/i;

-

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  AUTHOR AND COPYRIGHT

    Copyright (c) 1997-1999 Tom Christiansen and Nathan
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                                                           04.26
--
    This space intentionally left blank



Mon, 17 May 2004 08:17:01 GMT  
 
 [ 1 post ] 

 Relevant Pages 

1. Match starting from the nth occurrence of a character to the nth+1 occurrence

2. FAQ 4.28 How do I change the Nth occurrence of something?

3. FAQ 4.28 How do I change the Nth occurrence of something?

4. FAQ 4.28 How do I change the Nth occurrence of something?

5. FAQ 4.28 How do I change the Nth occurrence of something?

6. FAQ 4.28 How do I change the Nth occurrence of something?

7. FAQ 4.28 How do I change the Nth occurrence of something?

8. FAQ 4.28 How do I change the Nth occurrence of something?

9. FAQ 4.28 How do I change the Nth occurrence of something?

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12. FAQ: How do I change the Nth occurrence of something?

 

 
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