# Ruby comprehensive "slow" reference **URL:** \ **Category:** Ruby\ **Created:** [July 29, 2006, 12:08pm UTC](https://www.ruby-forum.com/t/ruby-comprehensive-slow-reference/100489 "2006-07-29T12:08:25Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![leslieviljoen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/3d9bf3/32.png) [@leslieviljoen](https://www.ruby-forum.com/u/leslieviljoen)\ **Post date:** [July 29, 2006, 12:08pm UTC](https://www.ruby-forum.com/t/ruby-comprehensive-slow-reference/100489/1 "2006-07-29T12:08:25Z")
Hi! I tried to find online explanations for the ‘%’ and ‘?’ operators used by Florian in an earlier post, but could not. The closest I saw were quick-references, but is there a comprehensive “slow” reference anywhere? None of the quick ones I saw listed those operators. Les ---
**Author:** ![leslieviljoen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/3d9bf3/32.png) [@leslieviljoen](https://www.ruby-forum.com/u/leslieviljoen)\ **Post date:** [July 29, 2006, 1:30pm UTC](https://www.ruby-forum.com/t/ruby-comprehensive-slow-reference/100489/2 "2006-07-29T13:30:28Z")
On 7/29/06, Leslie V. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hi! > > I tried to find online explanations for the ‘%’ and ‘?’ operators used The ?X syntax is described here: [http://www.rubycentral.com/book/language.html#UC](http://www.rubycentral.com/book/language.html#UC) In fact, it’s not an operator, it’s an integer literal. The % operator is described within it’s class, String, referencing syntax of Kernel#sprintf. When I started with ruby some time ago I was going crazy when I looked for something… Some pieces of information are scattered across too many places, especially Regexen are mentioned at three locations in the pickaxe book (1st edition) and I was hard to remember what piece is where. Now I got somewhat accustomed to this, so it’s no longer a problem for me. Now I mostly use rdoc and sometimes zenspider’s quickreference for bits that are missing from rdoc (or, that I still haven’t found there 😉 Now, what I want to say is, that maybe it would help to reorganize the docs a bit, or maybe just add some index pages to it I really appreciate all the hard work which made the current state possible, and the gradual enhacements that are being made. J. ---
**Author:** ![leslieviljoen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/3d9bf3/32.png) [@leslieviljoen](https://www.ruby-forum.com/u/leslieviljoen)\ **Post date:** [July 29, 2006, 1:30pm UTC](https://www.ruby-forum.com/t/ruby-comprehensive-slow-reference/100489/3 "2006-07-29T13:30:39Z")
> > > sender: “Leslie V.” date: “Sat, Jul 29, 2006 at 07:06:17PM +0900” \<\<\ > > Hi! > > > Hi, > I tried to find online explanations for the ‘%’ and ‘?’ operators used > by Florian in an earlier post, but could not. The closest I saw were > quick-references, but is there a comprehensive “slow” reference > anywhere? None of the quick ones I saw listed those operators. > Here’s one nice quick reference I just find a couple of days ago: > [Ruby | zenspider.com | by ryan davis](http://www.zenspider.com/Languages/Ruby/QuickRef.html) > Got that link from this site: > [http://mypage.bluewin.ch/yuppi/links/cheatsheets.html](http://mypage.bluewin.ch/yuppi/links/cheatsheets.html) > which may have references to other ruby quick refs as well, haven’t > taken a really good look at it. However, that one is still too quick 🙂 it does not explain what you need, but here is a short explanation: ? is a conditional operator, e.g. ``` a = (1 == 2) ? 3 : 4 # => 4 ``` % usually wears two hats… one is the modulus operator: ``` 5 % 4 # => 1 ``` the other one is to format strings: ``` "%08b" % 17 # => "00010001" "%02X" % 17 # => "11" ``` Hope it helps, Alex