From: Dave Thomas <Dave@...>
Date: 2001-11-05T23:46:18+09:00
Subject: [ruby-talk:24391] Re: documentation for builtin classes

Niko Schwarz <niko.schwarz@gmx.net> writes:

> Hello, Would someone give me a hint where to find up to date
> documentation for the builtin classes of ruby?  I don't find it, I
> always check in the pragmatic user guide, but it does not contain,
> e.g. the grep method (which i found by try and error *sigh*)

Grep is a method of the Enumerable module, which is mixed in to classes
such as Array:

    http://dev.rubycentral.com/book/ref_m_enumerable.html#grep


We decided not to include the documentation of (most) mixed in methods
in every class that uses them, as that would add quite a lot of bulk
to the reference.


If you download the 'ri' tool, you'd also be able to say



  dave[~/tmp 8:45:20] ri grep

  -------------------------------------------------------- Enumerable#grep
     enumObj.grep( pattern ) -> anArray
     enumObj.grep( pattern ) {| obj | block } -> anArray
  ------------------------------------------------------------------------
     Returns an array of every element in enumObj for which Pattern ===
     element. If the optional block is supplied, each matching element
     is passed to it, and the block's result is stored in the output
     array.

        (1..100).grep 38..44   #=> [38, 39, 40, 41, 42, 43, 44]
        c = IO.constants
        c.grep(/SEEK/)         #=> ["SEEK_END", "SEEK_CUR", "SEEK_SET"]
        res = c.grep(/SEEK/) {|v| IO.const_get(v) }
        res                    #=> [2, 1, 0]




Regards


Dave