Regex in if statemetn

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

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Re: Regex in if statement by toolic (Bishop) on Mar 18, 2014 at 19:41 UTC
Read Writeup Formatting Tips, then update your post using "code" tags only around your code. This should meet your requirements: `use warnings; use strict; while (<DATA>) { print if /^#\s*[a-z]+/i; } __DATA__ #MO # MO #mo # mo # 555` [download] If not... read the Basic debugging checklist	[reply] [d/l]
Re^2: Regex in if statement by finfan (Acolyte) on Mar 18, 2014 at 19:52 UTC
Doesn't seem to work. #MO and # MO do not match. Tried the regex tester at http://www.internetofficer.com/seo-tool/regex-tester/ and it says "no match"	[reply]
Re^3: Regex in if statement by 2teez (Vicar) on Mar 18, 2014 at 21:09 UTC
Hi finfan, ..Doesn't seem to work. #MO and # MO do not match. Tried the regex tester at http://www.internetofficer.com/seo-tool/regex-tester/ and it says "no match".. I know the code posted by toolic worked, I wanted to find out why it wasn't working on the website you mentioned. Tried it out and it worked with the following result: `Regular Expression Test Results Tested pattern: ^#\s*[a-z]+ Applied options: the comparison was case-insensitive String 1: #MO Result : true String 2: # MO Result : true String 3: #mo Result : true String 4: # mo Result : true String 5: # 555 Result : false` [download] May be the question, one should be asking is: How are you doing these regexp? If you tell me, I'll forget. If you show me, I'll remember. if you involve me, I'll understand. --- Author unknown to me	[reply] [d/l]
Re^3: Regex in if statement by kcott (Archbishop) on Mar 19, 2014 at 07:17 UTC
"Doesn't seem to work. #MO and # MO do not match." That sounds like you forgot the '`i`' modifier at the end of "`/^#\s[a-z]+/i`". "Tried the regex tester at http://www.internetofficer.com/seo-tool/regex-tester/ and it says "no match""* That site clearly states "We use Perl-style regular expressions." (not Perl regular expressions). It also seems to have limited functionality: it has a checkbox for the '`i`' modifier and nothing for any of the other modifiers (see `/PATTERN/msixpodualgc` in "perlop: Regexp Quote-Like Operators"). Why not try it in a real perl script. As ++toolic provided you with the complete code, it's a simple copy-paste operation. -- Ken	[reply] [d/l] [select]
Re^3: Regex in if statement by hippo (Archbishop) on Mar 18, 2014 at 19:57 UTC
Sure they do: `$ cat 1078855.pl use warnings; use strict; while (<DATA>) { print if /^#\s*[a-z]+/i; } __DATA__ #MO # MO #mo # mo # 555 $ perl 1078855.pl #MO # MO #mo # mo $` [download]	[reply] [d/l]
Re: Regex in if statemetn by Anonymous Monk on Mar 18, 2014 at 20:07 UTC
You're right, it shouldn't match an IP (unless you mean hostname?). Please provide some more sample input with comments on what should match and what shouldn't. With the limited specs you've given, here's a regex: `/^# ?(?:[A-Z]{2}\|[a-z]{2})/` That'll match any two uppercase letters or any two lowercase letters, but not mixed ("Mo"). If you want mixed case to match too: `/^# ?[A-Z]{2}/i` If you want to match only two letters, not more, stick a `\b` at the end of the regex.	[reply] [d/l] [select]
Re: Regex in if statemetn by frozenwithjoy (Priest) on Mar 19, 2014 at 12:42 UTC
Just in case you copied this snippet directly from your script, I wanted to let you know that in one place you are using `$input[$an]` and everywhere else using `$input[an]` (Note `$an` vs `an`)	[reply] [d/l] [select]