From: Stefan Matthias Aust <sma@3plus4.de>
Date: 2001-05-01T04:40:03+09:00
Subject: [ruby-talk:14452] How to do it the Ruby-way 3

First a question: Why is

 p (1..10).to_a

interpreted as

 (p (1..10)).to_a    >>  1..10

instead of

 p ((1..10).to_a)  >>  [1, ..., 10]

It gave me a hard time to figure this out, especially as "nil.to_a"
(nil is the result of p(..)) has a meaning and doesn't throw an error.

I would have expected that, if I leave a SPACE between the method name
and the open parenthesis, it is NOT taken as the argument to "p" but
instead the "." has a higher precedence.  At least this would be a
useful assumption IMHO.

But my actual and original question is another one.  In Squeak
Smalltalk, I can send #shuffle to an Array (or any
SequenceableCollection I think) to randomize an array.  Is there a
similar built-in mehtod in Ruby?  It's of course easy to add (see
below - code improvements are welcomed!), but it's so useful I'd like
to see it being part of the built-in stuff.

 class Array
   def shuffle
     clone.shuffle!
   end  
   def shuffle!
     len = length
     (0...len).each {|i|
       j = rand len
       self[i], self[j] = self[j], self[i]
     }
     self
   end
 end
 p ((1..100).to_a.shuffle)

BTW, is there just one global random number generator?


bye
--
Stefan Matthias Aust \/ Truth Until Paradox