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Re: Match a pattern only if it is not within another pattern

by pbeckingham (Parson)
on Aug 16, 2005 at 19:48 UTC ( #484226=note: print w/ replies, xml ) Need Help??


in reply to Match a pattern only if it is not within another pattern

Use negative look-behind and negative lookahead.

$str =~ s/((?<!bar)\S*)foo(\S*(?!qux))/${1}123${2}/gx;
Update: Yup - it's broke. Nothing to see here, move along.



pbeckingham - typist, perishable vertebrate.


Comment on Re: Match a pattern only if it is not within another pattern
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Re^2: Match a pattern only if it is not within another pattern
by Transient (Hermit) on Aug 16, 2005 at 19:51 UTC
    That gave me
    bl123 and barthis123thatqux and barso123quxhim and123som 123


    Update:
    However this seems to do what is intended, at least with the test string:
    $str =~ s/((?<!bar)\S*)foo((?!\S*qux))/${1}123${2}/gx;
    gives
    bl123 and barthisfoothatqux and barsofooquxhim and123som 123
Re^2: Match a pattern only if it is not within another pattern
by punkish (Priest) on Aug 16, 2005 at 19:53 UTC
    sorry, this doesn't work...
    $str =~ s/((?<!bar)\S*)foo(\S*(?!qux))/${1}123${2}/gx; print "$str\n";

    prints

    bl123 and barthis123thatqux and barso123quxhim and123som 123
    --

    when small people start casting long shadows, it is time to go to bed

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