NT paths and regexp

tent8f has asked for the wisdom of the Perl Monks concerning the following question:

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Re: NT paths and regexp (\Q) by tye (Sage) on Sep 12, 2003 at 17:05 UTC
That is because you wrote the wrong code: `print "Do they match ? : "; print $filename_a =~ /\Q$filename_b\E/ ; # output is 1` [download] Always remember: `/$regex/ /\Q$string\E/` [download] If you use a variable as part of a regex, Perl needs to know if you want to interpret that variable as a string or as a regex. The default is to interpret it as a regex. If you want to use a string (from a variable) in a regex, then you need to tell Perl that by using \Q (or quotemeta, though this is can't be used as easily directly in the regex). - tye	[reply] [d/l] [select]
Re: NT paths and regexp by Abigail-II (Bishop) on Sep 12, 2003 at 14:43 UTC
That's because `"\\a"` still has a backslash, and backslashes followed by a letter may have a special meaning for the regex. `/\a/` matches a bell character (^G), and not a backslash followed by an a. In general, `$str =~ /$str/` is often not a match due to the special meaning of characters in $str. Abigail	[reply] [d/l] [select]
Re: NT paths and regexp by tcf22 (Priest) on Sep 12, 2003 at 14:43 UTC
The string is being interpolated again, so you need \ x4. `$filename_b = "c:\\\\abc.log";` [download] but then the eq won't work. You could also use the magic of qr// `$filename_a = "c:\\abc.log"; $filename_b = "c:\\abc.log"; $filename_b_re = qr/c:\\abc.log/; print "Are they equal ? : "; print $filename_a eq $filename_b ; # output is 1 print "\n"; print "Do they match ? : "; print $filename_a =~ /$filename_b_re/ ; # output is 1` [download] Another option(prefered, at least by me) is to use / instead of \\ `$filename_a = "c:/abc.log"; $filename_b = "c:/abc.log";` [download] - Tom	[reply] [d/l] [select]
Re: NT paths and regexp by Abigail-II (Bishop) on Sep 12, 2003 at 14:47 UTC
You could also use the magic of qr// But only if you cut-and-paste the string, not if you do: `$filename_b_re = qr /$filename_b/;` [download] It's not the magic of qr that makes it work, it's the magic of cut-and-paste. This will work too: `print $filename_a =~ /c:\\abc.log/; # output is 1` [download] Abigail	[reply] [d/l] [select]
Re: Re: NT paths and regexp by tcf22 (Priest) on Sep 12, 2003 at 14:53 UTC
I know, I was giving some options. Like i said, the way I prefer to do it is using `c:/abc.log`. NT sees it as a valid path, and you don't have to worry about escaping anything. - Tom	[reply] [d/l]