help on reg ex

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

Replies are listed 'Best First'.
Re: help on reg ex by artist (Parson) on May 07, 2003 at 15:22 UTC
`$a = '/export/home/test/great'; if($a =~ m/(.)\/(.?)$/){ $dir = $1; $file = $2; } print "$a\n$dir\n$file\n"; __END__ /export/home/test/great /export/home/test great` [download] Now, what is the purpose behind it..? is it to get directory out of the total path or just the filename?. Use File::Basename. If you give more contextual hints, more help is awaiting for you. artist	[reply] [d/l]
Re: help on reg ex by Improv (Pilgrim) on May 07, 2003 at 15:21 UTC
I'm assuming your second example of $a is a typo and should have read $a = '/export/home/test'. If you want to chop out great specifically, you can do: `$a =~ s/\/great$//;` [download] If you want to generically remove the last element, and save it to $bar, you can do: `$a =~ s/(\/.*)$//; $bar = $1;` [download] I hope this helps.	[reply] [d/l] [select]
(z) Re^2: help on reg ex by zigdon (Deacon) on May 07, 2003 at 16:23 UTC
Your example: `$a =~ s/(\/.)$//; $bar = $1;` [download] would put in $bar everything starting from the first slash. You should instead do: `$a =~ s#(/[^/])$##; $bar = $1;` [download] -- zigdon	[reply] [d/l] [select]
Re: (z) Re^2: help on reg ex by Improv (Pilgrim) on May 07, 2003 at 17:16 UTC
Oops, you're right. My bad -- I don't know what I was thinking :) You provide a good example to the user of a case where it's a good idea to use a nonstandard regex delimiter, BTW. Cool.	[reply]
Re: help on reg ex by svsingh (Priest) on May 07, 2003 at 15:39 UTC
I'm not really clear on what you're asking for with extracting /great and putting it back. Both the inital and resulting $a's in your question look the same to me. Here's what I came up with... `my $a = '/export/home/test/great'; $a =~ / (.) (\/[^\/]) /x; my $front = $1; my $back = $2; print "a: $a\n"; print "front: $front\n"; print "back: $back\n";` [download] Note: I'm using /x to add some whitespace to the regex for clarity. You can ignore the spaces. That returns... `a: /export/home/test/great front: /export/home/test back: /great` [download] I think the other solutions are affected by regex greed. So they'll pull out the longest string starting with a slash. If I'm oversimplifying things, then I'm sorry. I hope this helps.	[reply] [d/l] [select]
Re: Re: help on reg ex by Anonymous Monk on May 20, 2003 at 15:55 UTC
I must have forgotten to thank you , thanks for helping me out	[reply]
Re: help on reg ex by Joost (Canon) on May 07, 2003 at 15:23 UTC
I assume you mean: `$a="export/home/test/great/great";` [download] you can do: `$a =~ s#/great\z##; print $a; # prints "/export/home/test/great"` [download] (that `\z` means 'the end of the string') `-- Joost downtime n. The period during which a system is error-free and immune from user input.` [download]	[reply] [d/l] [select]