# Regexp help **URL:** \ **Category:** Ruby\ **Created:** [September 18, 2007, 11:12pm UTC](https://www.ruby-forum.com/t/regexp-help/114933 "2007-09-18T23:12:04Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 18, 2007, 11:12pm UTC](https://www.ruby-forum.com/t/regexp-help/114933/1 "2007-09-18T23:12:04Z")
K, so I suck at regular expressions. I just don’t seem to understand them. What I want to do is determine if a string includes 2 special characters a semi-colon and a question mark. Here’s my example that I’m trying to work with. irb(main):009:0\> encoding = “;6277200301500269=?” =\> “;6277200301500269=?” irb(main):010:0\> encoding.include?(%r{;?}.to\_s) =\> false irb(main):011:0\> I want this to return true, but it doesn’t Can anyone help me out? thanks, ~Jeremy ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 18, 2007, 11:21pm UTC](https://www.ruby-forum.com/t/regexp-help/114933/2 "2007-09-18T23:21:48Z")
Jeremy W. wrote: > What I want to do is determine if a string includes 2 special characters > a semi-colon and a question mark. You don’t need regular expressions to do that, try this instead: irb\> encoding.include? “;” and encoding.include? “?” =\> true On the other hand, if you want to use regular expressions regardless, you should notice that String#include? takes a string rather than a Regexp. Note that: irb\> %r{;?}.to\_s > “(?-mix:;\?)” So encoding.include?(%r{;?}.to\_s) is equivalent to encoding.include?("(?-mix:;\?)") which is not going to succeed. To use a regexp, try: irb\> encoding =~ /(;._?)|(?._;)/ =\> true. best Dan ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 12:46am UTC](https://www.ruby-forum.com/t/regexp-help/114933/3 "2007-09-19T00:46:10Z")
On Sep 18, 4:04 pm, Jeremy W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > On the other hand, if you want to use regular expressions regardless, > > is equivalent to > > irb(main):004:0\> > > So what does the 0 mean? 0 matches? If all else fails, I will use the > ugly version 🙂 It means that it found the first match starting at index 0 in the string. (Try reading the documentation on the =~ method.) Note that the supplied regexp will fail if your string has a newline in it. You may want to append the ‘m’ (multiline) modifier to it, e.g. /;._?|?._;/m (There’s also no need for the parentheses, and a minor theoretical speed/memory reason to leave them off.) ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 12:04am UTC](https://www.ruby-forum.com/t/regexp-help/114933/4 "2007-09-19T00:04:47Z")
Daniel L. wrote: > Jeremy W. wrote: > > > What I want to do is determine if a string includes 2 special characters > > a semi-colon and a question mark. > > You don’t need regular expressions to do that, try this instead: > > irb\> encoding.include? “;” and encoding.include? “?” > =\> true > > On the other hand, if you want to use regular expressions regardless, > you should notice that String#include? takes a string rather than a > Regexp. > > Note that: > irb\> %r{;?}.to\_s > > > “(?-mix:;\?)” > > So > encoding.include?(%r{;?}.to\_s) > > is equivalent to > encoding.include?("(?-mix:;\?)") > > which is not going to succeed. > > To use a regexp, try: > irb\> encoding =~ /(;._?)|(?._;)/ > =\> true. > > best > Dan Thanks for the help. I would like to use a regexp becuase I think it will look nicer in the code. I tried your example and got C:\rails\_apps\hotswipe\>irb irb(main):001:0\> require ‘config/environment’ =\> true irb(main):002:0\> encoding = “;6277200301500269=?” =\> “;6277200301500269=?” irb(main):003:0\> encoding =~ /(;._?)|(?._;)/ =\> 0 irb(main):004:0\> So what does the 0 mean? 0 matches? If all else fails, I will use the ugly version 🙂 thanks, ~Jeremy ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 12:53am UTC](https://www.ruby-forum.com/t/regexp-help/114933/5 "2007-09-19T00:53:38Z")
Gavin K. wrote: > It means that it found the first match starting at index 0 in the > string. (Try reading the documentation on the =~ method.) ok, that makes sense. I did check out the docs on [http://www.ruby-doc.org/core/](http://www.ruby-doc.org/core/) I clicked the =~ method under Regexp and it sends me to rxp.match(str) =\> matchdata or nil Returns a MatchData object describing the match, or nil if there was no match. This is equivalent to retrieving the value of the special variable $~ following a normal match. which didn’t say anything about indexes. Are there any other sites that have different documentation? ~Jeremy ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 12:55am UTC](https://www.ruby-forum.com/t/regexp-help/114933/6 "2007-09-19T00:55:04Z")
Jeremy W. wrote: > Gavin K. wrote: > > > It means that it found the first match starting at index 0 in the > > string. (Try reading the documentation on the =~ method.) > > ok, that makes sense. I did check out the docs on > [RDoc Documentation](http://www.ruby-doc.org/core/) > I clicked the =~ method under Regexp and it sends me to > rxp.match(str) =\> matchdata or nil > Returns a MatchData object describing the match, or nil if there was no > match. This is equivalent to retrieving the value of the special > variable $~ following a normal match. > > which didn’t say anything about indexes. Are there any other sites that > have different documentation? > > ~Jeremy haha, ok you can disregard that, I looked under string and seen what you were talking about. My bad. thanks ~Jeremy ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 5:40am UTC](https://www.ruby-forum.com/t/regexp-help/114933/7 "2007-09-19T05:40:32Z")
From: Jeremy W. [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] # What I want to do is determine if a string includes 2 special # characters a semi-colon and a question mark. # irb(main):009:0\> encoding = “;6277200301500269=?” # =\> “;6277200301500269=?” # irb(main):010:0\> encoding.include?(%r{;?}.to\_s) # =\> false start simple, check if a string contains a ; or ? irb(main):095:0\> encoding[/;|?/] =\> “;” check if a string starts w a ; and ends with a ? irb(main):096:0\> encoding[/^;.\*?$/] =\> “;6277200301500269=?” string[regex] returns the matched (sub)string (wc is true in ruby) otherwise it returns nil (wc is false in ruby) kind regards -botp ---
**Author:** ![nuby2ruby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/54ee81/32.png) [@nuby2ruby](https://www.ruby-forum.com/u/nuby2ruby)\ **Post date:** [September 19, 2007, 1:38pm UTC](https://www.ruby-forum.com/t/regexp-help/114933/8 "2007-09-19T13:38:44Z")
If it’s going to be going heavy on the regexp… (I have no shame) Try TextualRegexp. Seriously, it was written so you DON"T have to hurt your brain over it. ~ Ari English is like a pseudo-random number generator - there are a bajillion rules to it, but nobody cares.