Look ahead & Look behind

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

Hello Monks,

I have looked @ perlre documentation but still not able to understand how they work.

Can someone tell me how it works by examples.

Comment on Look ahead & Look behind

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Re: Look ahead & Look behind by toolic (Bishop) on Apr 03, 2010 at 00:23 UTC
If you follow the link to perlretut from perlre:SEE-ALSO, there are examples in Looking ahead and looking behind	[reply]
Re: Look ahead & Look behind by ikegami (Patriarch) on Apr 03, 2010 at 00:30 UTC
Compare `( $_ = 'abcba' ) =~ s/b//g; # aca ( $_ = 'abcba' ) =~ s/bc//g; # aba ( $_ = 'abcba' ) =~ s/b(?=c)//g; # acba` [download] Compare `( $_ = '!a!b!c!' ) =~ s/!.!/!_!/g; # !_!b!_! ( $_ = '!a!b!c!' ) =~ s/!.(?=!)/!_/g; # !_!_!_! ( $_ = '!a!b!c!' ) =~ s/(?<=!).(?=!)/_/g; # !_!_!_!` [download]	[reply] [d/l] [select]
Re^2: Look ahead & Look behind by ambrus (Abbot) on Apr 03, 2010 at 16:43 UTC
Nice example. Regexen similar to the last few came up in Re: phrase match.	[reply]
Re: Look ahead & Look behind by roboticus (Chancellor) on Apr 03, 2010 at 00:25 UTC
Examples are all over the place. Why not look for them? Google and Super Search would be likely candidates. If you have a question about any of the specifics, let us know where you need help. ...roboticus	[reply]
Re: Look ahead & Look behind by Anonymous Monk on Apr 03, 2010 at 00:59 UTC
But perlre includes examples	[reply]

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