Re^2: Regular Expression - pattern matching

Hi Darren,

I need to get the preferred patterns from the @str array.As i don't have a any general/common rule to due to different patterns,i guess the following assumption can yield the good results.

My assumptions are,

#. check the number of characters before the first "_" (underscore).
#. If it's return only two characters, then get the string untill it reach the second "_"(underscore) from the string else if more than 2 characters then it must be a targetted pattern.
#. I guess i can't able to use the "\w" (word) pattern, because it will take the whole string as a word.

Thank you in advance.
-kulls

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Re^3: Regular Expression - pattern matching by McDarren (Abbot) on Feb 22, 2006 at 10:21 UTC
#. check the number of characters before the first "_" (underscore). #. If it's return only two characters, then get the string untill it reach the second "_"(underscore) Okay, well because you are looking for anything that is not an underscore, then a negated character class is probably the way to go. Something like this: `if (/^([^_]{2}_[^_]+)_/) { print $1; }` [download] else if more than 2 characters then it must be a targetted pattern Sorry, but I don't get that. What is a "targetted pattern"? I guess i can't able to use the "\w" (word) pattern, because it will take the whole string as a word. Yes and no. It's okay, because you are limiting it to only the first two characters with `{2}`. But it's probably not okay because \w will also match an underscore. So \w{2} would match something like "_a", which I'm pretty sure you don't want. Cheers, Darren :)	[reply] [d/l] [select]
Re^4: Regular Expression - pattern matching by kulls (Hermit) on Feb 22, 2006 at 12:44 UTC
Hi Darren, I'm looking for the pattern like "xxxxx" if it's "xxxx_sssss" and also if it's "xx_ssss" then i need "xx_ssss" . I have reuse your code `if (/^([^_]{2}_[^_]+)_/) { print $1; }` [download] and it looks like `for(@str) { my $temp; if (/^([^_]{2}_[^_]+)_/) { $temp=$1; print $temp."\n"; } else { ($temp)=$_=~/^([a-z0-9]+)\_/xi; print $temp."\n"; } }` [download] Unfortunately i didn't get the exact pattern which i showed in my output earlier. Can you please correct me if i'm wrong ?? Thank you in advance. -kulls	[reply] [d/l] [select]
Re^5: Regular Expression - pattern matching by McDarren (Abbot) on Feb 22, 2006 at 17:55 UTC
Okay, after scratching my head for about 20 minutes, I think I've worked out what you want. If the first two characters are not underscores, but the third character is - then keep everything up to (but not including) the second underscore. Otherwise... Keep everything up to (but not including) the first underscore. Is that correct? If yes, then the following should do it: `for (@strings) { my $temp = ""; if (($temp) = $_ =~ m/^([^_]{2}_[^_]+)_?/) { print $temp; } elsif (($temp) = $_ =~ m/^([^_]+)/) { print $temp; } }` [download] Update: Oh, one thing I forgot to point out, was that there was an error in the code in my earlier reply. I hadn't accounted for the fact that there may not be any underscores at all. That's been fixed in the above snippet.	[reply] [d/l]