seeking expression to match "/mysearch/detail/966031"

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

Hello very smart monks. I'm trying to match the following text in a text file: "/newsearch/detail/96603" I actually have a bunch of these and I can fish most things out and get them into another text file but this string is stumping me. I think it's the '/' that's messing me up. The text starts the same way but the trailing number are all different. Here is my code:

#push @matches, $_ if /^.*?(?:\b|_)$parse1(?:\b|_).*?(?:\b|_)$parse2(?:\b|_).*?$/m;

I tried "/newsearch/detail/" for $parse1 and a blank $parse2 and several other things but no luck. Thanks in advance for any help you can provide this monk in training!

Comment on seeking expression to match "/mysearch/detail/966031" Download Code

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Re: seeking expression to match "/mysearch/detail/966031" by AnomalousMonk (Archbishop) on Nov 18, 2016 at 18:50 UTC
The basic problem stems from a too-liberal use of the `(?:\b\|_)` assertion. The `$parse1` string begins with a `/` (forward slash) character. This is not a `\w` character. The `(?:\b\|_)` assertions in `(?:\b\|_)$parse1(?:\b\|_)` require that `$parse1` be preceded by a `\w` character or a `_` (underscore) (note that `_` is a member of the `\w` class), and followed by a non-`\w` character or a `_` (underscore). What the OPed regex will match depends on the string it is matching against. I would advise giving us examples of typical strings. Below are some examples of mine that show various matches/non-matches: c:\@Work\Perl>perl -wMstrict -le "print qq{perl version: $] \n}; ;; my $parse1 = '/newsearch/detail/96603'; my $parse2 = ''; ;; for ( qq{xxx \n/newsearch/detail/96603\n xxx}, qq{xxx \n/newsearch/detail/96603x\n xxx}, qq{xxx \nx/newsearch/detail/96603x\n xxx}, qq{xxx \nx/newsearch/detail/96603\n xxx}, qq{bla vla/newsearch/detail/96603 x}, ) { print qq{<<$_>>}; print qq{MATCH '$&'} if /^.?(?:\b\|_)$parse1(?:\b\|_).?(?:\b\|_)$parse2(?:\b\|_).?$/m; print ''; } " perl version: 5.008009 <<xxx /newsearch/detail/96603 xxx>> <<xxx /newsearch/detail/96603x xxx>> <<xxx x/newsearch/detail/96603x xxx>> <<xxx x/newsearch/detail/96603 xxx>> MATCH 'x/newsearch/detail/96603' <<bla vla/newsearch/detail/96603 x>> MATCH 'bla vla/newsearch/detail/96603 x' [download] Update:* Because you give no examples of the typical strings you're matching against, I cannot understand the implications of the `^.?` and `.?$` and `.*?(?:\b\|_)$parse2(?:\b\|_)` portions of the OPed regex (which I suspect may be superfluous), or why you are matching in `/m` "multi-line" mode. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re: seeking expression to match "/mysearch/detail/966031" by Discipulus (Canon) on Nov 18, 2016 at 15:56 UTC
You must escape `/` in regexes: `perl -e "print $1 if $ARGV[0]=~/(\/newsearch\/detail\/96603)/" "bla vl +a/newsearch/detail/96603 x" /newsearch/detail/96603` [download] You can also choose a different delimiter instead of `/` see `perlrequick` for details and this way you prevent the leaning toothpick syndrome L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re^2: seeking expression to match "/mysearch/detail/966031" by AnomalousMonk (Archbishop) on Nov 18, 2016 at 19:16 UTC
You must escape / in regexes ... A literal delimiter character in a regex like `/...\/.../` must be escaped, but if the delimiter is within an interpolated string (as in the OPed regex), the regex compiler is quite happy with it: `c:\@Work\Perl>perl -wMstrict -le "my $re = '.../...'; ;; print 'match' if 'xxx/xxx' =~ /$re/; " match` [download] Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]