using grep with multiple "+"

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

I'm trying to use grep to compare a directory path such as C:\apps\c++\application with an array of certain file types (e.g. .cpp, .hpp etc) residing on the hard drive, some of which are in the C:\apps\c++\application directory.

The line:
@fileList = grep{/$dirPath/} @allFiles;
works for directories which do not have the plus symbol in their path but not for ones which do. I've tried escaping the plus characters so in effect it's doing:

grep {/c:/apps/c\+\+/application/} c:/apps/c++/application/myfile.cpp

but none of the files in the C++ directory are being returned and if I unescape the "+" I get an error saying "nested quanitfiers in regex"

Any help would be greatly appreciated

Thanks
Steve

Comment on using grep with multiple "+"

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Re: using grep with multiple "+" by zejames (Hermit) on Sep 14, 2004 at 13:10 UTC
Protect your path by using \Q \E : `my $dirPath = 'c:\apps\c++\application'; print grep { /\Q$dirPath\E/ } ('c:\apps\c++\application\myfile.cpp');` [download] Then, the + won't be interpreted in the regular expression. Kind regards -- zejames	[reply] [d/l]
Re: using grep with multiple "+" by ihb (Deacon) on Sep 14, 2004 at 13:11 UTC
Use the quotemeta() function or the "\Q..." construct. Read more about it in perlfunc. `ihb` Read argumentation in its context!	[reply] [d/l]
Re^2: using grep with multiple "+" by Anonymous Monk on Sep 14, 2004 at 13:23 UTC
zejames, ihb that worked like a treat. Just what I was looking for. Many Thanks Steve	[reply]
Re: using grep with multiple "+" by qumsieh (Scribe) on Sep 14, 2004 at 16:10 UTC
Using `quotemeta()` or `\Q..\E` as suggested by others is the correct thing to do. The reason your regexp was failing was the existence of too many forward slashes. Either use a different delimeter, or escape your forward slashes in your pattern: `grep m\|c:/apps/c\+\+/application\| => 'c:/apps/c++/application/myfile.cpp'; grep /c:\/apps\/c\+\+\/application/ => 'c:/apps/c++/application/myfile.cpp';` [download]	[reply] [d/l] [select]
Re: using grep with multiple "+" by Anonymous Monk on Sep 14, 2004 at 13:05 UTC
Note for the line grep {/c:/apps/c\+\+/application/} c:/apps/c++/application/myfile.cpp It should read grep {/c:/apps/c\+\+/application/} c:/apps/c\+\+/application/myfile.cpp	[reply]