treating * as a normal character in a regex

chuleto1 has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: regexp =~ by japhy (Canon) on Jul 29, 2002 at 18:05 UTC
First, you want to use `/\Q$line\E/`. Second, why are you doing `if (/$x/) { s/$x/$y/g }` instead of the simpler `s/$x/$y/g`? _____________________________________________________ Jeff`[japhy]`Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area) `s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;`	[reply] [d/l] [select]
Re: regexp =~ by redsquirrel (Hermit) on Jul 29, 2002 at 17:50 UTC
`... if($theMatch =~ /\Q$line\E/ ) ...` [download] The `\Q` and `\E` start and stop metacharacter escaping, respectively. --Dave	[reply] [d/l] [select]
Re: regexp =~ by thelenm (Vicar) on Jul 29, 2002 at 17:50 UTC
You should use `\Q` and `\E`, which put backslashes before special characters. The regex should look something like this: `$theMatch =~ /\Q$line\E/` [download] Also, are you trying to perform a substitution on `$theMatch` or `$line`? You're actually performing a substitution on `$_` (which is probably not what you want). -- Mike `-- just,my${.02}`	[reply] [d/l] [select]
Re: regexp =~ by talexb (Chancellor) on Jul 29, 2002 at 17:49 UTC
Have you tried escaping the '' with a '\' in your regexp? --t. alex* "Mud, mud, glorious mud. Nothing quite like it for cooling the blood!" --Michael Flanders and Donald Swann	[reply]
Re: regexp =~ by kvale (Monsignor) on Jul 29, 2002 at 17:50 UTC
To quote regexp metacharacters, use the `\Q ... \E` quoting ops: `if($theMatch =~ /\Q$line\E/ )` [download] -Mark	[reply] [d/l] [select]
Re: regexp =~ by BrowserUk (Patriarch) on Jul 29, 2002 at 17:49 UTC
Escape the star eg. "THIS TEXT HAS A \* IN IT"; Baskslash will escape special chars in a regex! If your regex string is not going to be interpolated twice. Otherwise it's definately best to ignore this monk's advice and skip to the next answer:) UpdateGrrr. It worked fine in my test program ..mutter mutter mutter...:( `C:\test>perl -w "$_ = 'aaaaaaaaaaaaaabbbbbbbbbbb'; print 'Found it!' +if (/\/);" Can't open perl script "$_ = 'aaaaaaaaaaaaaabbbbbbbbbbb'; print 'Foun +d it!' if (/\/ );": Invalid argument C:\test>perl -we "$_ = 'aaaaaaaaaaaaaabbbbbbbbbbb'; print 'Found it!' + if (/\/);" Found it! C:\test>perl -we "$_ = 'aaaaaaaaaaaaaabbbbbbbbbbb'; print 'Found it!' +if (/\*/);" C:\test>` [download] Shame I felt so silly that I (had to) tested it, that I chose not to post the horribly complicated test prog. <cockney>Say la vee </cockney>:) And yes, I 'wasted' a vote and ++ Mr. AM. That guy amazes me, one time s/he asks the most trivial of questions, other times s/he responds with such knowledgable answers. Sometimes for several sometimes on the same day. It's almost like s/he has a split personality??	[reply] [d/l]
Re: Re: regexp =~ by Anonymous Monk on Jul 29, 2002 at 17:58 UTC
Escape the star eg. "THIS TEXT HAS A \ IN IT";* Note, that will not fix the problem. Try it and see. You need to use single quotes and a backslash, double quotes and two backslashes, or better, \Q and \E as suggested by others.	[reply]
Re: regexp =~ by Nightblade (Beadle) on Jul 29, 2002 at 17:50 UTC
please read perlre manpage about regexps. * must be escaped using slash `\*`	[reply] [d/l]


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