Sort_by{rand} doesn't shuffle array

ruby-talk
1

I did some searching on how to shuffle an array, and found
sort_by{rand}. However, if I call it, it doesn't make a change to my
array at all. I've got a class like this
class MyClass
  def initialize
    # Populate the array
    @my_array = Array.new
    ...
  end

  def shuffle!
    @my_array.sort_by{rand}
  end
end

If I call shuffle! from my code, the array's elements are still in the
order that they were created. Why are they not being shuffled like I
want?

2

  def shuffle!
    @my_array.sort_by{rand}

      @my_array = @my_array.sort_by{rand}

···

On Tue, Jan 03, 2006 at 07:03:42PM +0900, Pat Maddox wrote:

  end
end

--
Mauricio Fernandez

3

Mauricio Fernandez wrote:

def shuffle!
   @my_array.sort_by{rand}
   

     @my_array = @my_array.sort_by{rand}

or @my_array.sort_by! { rand }

···

On Tue, Jan 03, 2006 at 07:03:42PM +0900, Pat Maddox wrote:

end
end
   

4

or @my_array.sort_by! { rand }

Except that sort_by! does not exist :wink: (at least not in 1.8.4)

···

--
Sylvain

5

RUBY_RELEASE_DATE # => "2005-12-24"
RUBY_VERSION # => "1.8.4"
%w[a b c d].sort_by!{rand} # =>
# ~> -:3: undefined method `sort_by!' for ["a", "b", "c", "d"]:Array (NoMethodError)

···

On Tue, Jan 03, 2006 at 08:54:33PM +0900, Devin Mullins wrote:

Mauricio Fernandez wrote:

>On Tue, Jan 03, 2006 at 07:03:42PM +0900, Pat Maddox wrote:
>
>
>> def shuffle!
>> @my_array.sort_by{rand}
>>
>>
> @my_array = @my_array.sort_by{rand}
>
>
or @my_array.sort_by! { rand }

--
Mauricio Fernandez

6

Mauricio Fernandez wrote:

···

On Tue, Jan 03, 2006 at 08:54:33PM +0900, Devin Mullins wrote:

or @my_array.sort_by! { rand }
   
RUBY_RELEASE_DATE # => "2005-12-24"
RUBY_VERSION # => "1.8.4"
%w[a b c d].sort_by!{rand} # => # ~> -:3: undefined method `sort_by!' for ["a", "b", "c", "d"]:Array (NoMethodError)

3.times { Hand.smack!(Head) }