Re: 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;
[download]

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 Download Code

Replies are listed 'Best First'.
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` [download] Update: However this seems to do what is intended, at least with the test string: `$str =~ s/((?<!bar)\S)foo((?!\Squx))/${1}123${2}/gx;` [download] gives `bl123 and barthisfoothatqux and barsofooquxhim and123som 123` [download]	[reply] [d/l] [select]
Re^2: Match a pattern only if it is not within another pattern by punkish (Priest) on Aug 16, 2005 at 19:53 UTC
sorry, this doesn't work... `$str =~ s/((?<!bar)\S)foo(\S(?!qux))/${1}123${2}/gx; print "$str\n";` [download] prints `bl123 and barthis123thatqux and barso123quxhim and123som 123` [download] -- when small people start casting long shadows, it is time to go to bed	[reply] [d/l] [select]