Is rdoc (http://www.ruby-doc.org/core/) complete?

Ruby
1

Hello Team,

Although I have over a dozen Ruby books (and still do not master the
language) I try to make frequent use of the online documentation, rdoc,
located at: RDoc Documentation.
However, I was searching the rdoc for a method I new existed by
reading “The
Ruby Way - Second Edition By: Hal” but could not find it. The method
was *
find_all* which is part of Array class. I then looked a bit further
and
noticed that a sizable number of methods for the same class are not
found at
rdoc.

Since carrying books is a bit difficult a time, is there a definitive
site,
book, or whatever where I can find all the docs for a given release of
Ruby?

Thank you

Victor

2

On Thursday 22 May 2008, Victor R. wrote:

Since carrying books is a bit difficult a time, is there a definitive site,
book, or whatever where I can find all the docs for a given release of
Ruby?

Thank you

Victor

find_all is not a method of the Array class, but an instance method of
the
Enumerable module, which is mixed-in in class Array. If you look at the
online
documentation for Array, you’ll see that there’s a section called
“Included
Modules”, which contains Enumerable. Clicking on it, you’ll be directed
to the
documentation for the Enumerable module, knowing that all its instance
methods
are also instance methods of Array.

Stefano

3

On May 22, 5:30 pm, Victor R. [email protected] wrote:

4

On May 22, 2:51 pm, Albert S. [email protected] wrote:

Victor R. wrote:

The method was find_all which is part of Array class.

This method belongs in the Enumerable module, which Array included. Do
“ri find_all”

It’s not easy for new user’s to know where to look for such
information. I think it should be trivial for rdoc to reveal inherites/
included methods from other modules when searching for them in other
classes or modules that include them. IMHO, “ri Array#find_all” should
give a meaningful result since find_all is well-defined for Array
instances.

Lars

5

Victor R. wrote:

The method was find_all which is part of Array class.

This method belongs in the Enumerable module, which Array included. Do
“ri find_all”

6

On Thu, May 22, 2008 at 3:11 PM, Victor R. [email protected]
wrote:

Please forgive my ignorance and thank you for the information.

I have an array of integers with a minimum of 9 elements and a maximum of
81.
I need to count the frequency of each digit (1…9).
That’s why I was looking into the use of find_all or some other util that
would make my code simple. Otherwise I would have to loop and count the old
fashion way.

This is a typical way:

irb(main):001:0> a = [1,2,3,4,3,2,1,2,3,4,5,6,5,4,3,4,5,6,7,8,7,8,9]
=> [1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9]
irb(main):002:0> h = Hash.new {|h,k| h[k] = 0}
=> {}
irb(main):003:0> a.each {|x| h[x] += 1}
=> [1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9]
irb(main):004:0> h
=> {5=>3, 6=>2, 1=>2, 7=>2, 2=>3, 8=>2, 3=>4, 9=>1, 4=>4}

or:

irb(main):005:0> h2 = Hash.new(0)
=> {}
irb(main):006:0> a.each {|x| h2[x] += 1}
=> [1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9]
irb(main):007:0> h2
=> {5=>3, 6=>2, 1=>2, 7=>2, 2=>3, 8=>2, 3=>4, 9=>1, 4=>4}

Jesus.

7

Please forgive my ignorance and thank you for the information.

I have an array of integers with a minimum of 9 elements and a maximum
of
81.
I need to count the frequency of each digit (1…9).
That’s why I was looking into the use of find_all or some other util
that
would make my code simple. Otherwise I would have to loop and count the
old
fashion way.

Thank you

Victor

On Thu, May 22, 2008 at 8:49 AM, Stefano C.
[email protected]

8

Thank you all.
Jesús, thank you for the code snippet.

On Thu, May 22, 2008 at 10:02 AM, Jesús Gabriel y Galán <

9

From: Victor R. [mailto:[email protected]]
#thank you for the code snippet.

also try ruby1.8.7 or ruby1.9

036:0> a
=> [1, 2, 3, 4, 3, 2, 1, 2, 3, 4, 5, 6, 5, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9]

037:0> a.group_by{|k| k }.inject({}){|h,(k,v)| h[k] = v.size; h }
=> {1=>2, 2=>3, 3=>4, 4=>4, 5=>3, 6=>2, 7=>2, 8=>2, 9=>1}

10

The beauty of Ruby!
Many and elegant ways to solve a problem!

Thanks guys!

Victor