Methods
Public Instance methods
at_rand()

Return a random element of the array. 

  [1, 2, 3, 4].at_rand           #=> 2
  [1, 2, 3, 4].at_rand           #=> 4

[ show source ]

# File lib/more/facets/random.rb, line 104
    def at_rand
      self.at( rand( size ) )
    end
at_rand!()

Same as at_rand, but acts in place removing a random element from the array. 

  a = [1,2,3,4]
  a.at_rand!       #=> 2
  a                #=> [1,3,4]

[ show source ]

# File lib/more/facets/random.rb, line 115
    def at_rand!
      return delete_at( Random.number( size ) )
    end
pick(n=nil)

Similar to at_rand, but will return an array of randomly picked exclusive elements if given a number.

[ show source ]

# File lib/more/facets/random.rb, line 121
    def pick(n=nil)
      if n
        a = self.dup
        a.pick!(n)
      else
        at( Random.number( size ) )
      end
    end
pick!(n=nil)

Similar to at_rand!, but given a number will return an array of exclusive elements.

[ show source ]

# File lib/more/facets/random.rb, line 132
    def pick!(n=nil)
      if n
        if n > self.size
          r = self.dup
          self.replace([])
          r
        else
          r = []
          n.times { r << delete_at( Random.number( size ) ) }
          r
        end
      else
        delete_at( Random.number( size ) )
      end
    end
rand_index()

Random index.

[ show source ]

# File lib/more/facets/random.rb, line 150
    def rand_index
      rand( size )
    end
rand_subset( number=nil, exclusive=true )

Returns a random subset of an Array. If a number of elements is specified then returns that number of elements, otherwise returns a random number of elements upto the size of the Array.

By defualt the returned values are exclusive of each other, but if exclusive is set to false, the same values can be choosen more than once.

When exclusive is true (the default) and the number given is greater than the size of the array, then all values are returned. 

  [1, 2, 3, 4].rand_subset(1)        #=> [2]
  [1, 2, 3, 4].rand_subset(4)        #=> [2, 1, 3, 4]
  [1, 2, 3, 4].rand_subset           #=> [1, 3, 4]
  [1, 2, 3, 4].rand_subset           #=> [2, 3]

[ show source ]

# File lib/more/facets/random.rb, line 172
    def rand_subset( number=nil, exclusive=true )
      number = rand( size ) unless number
      number = number.to_int
      #return self.dup if (number >= size and exlusive)
      return sort_by{rand}.slice(0,number) if exclusive
      ri =[]; number.times { |n| ri << rand( size ) }
      return values_at(*ri)
    end
shuffle()

Randomize the order of an array. 

  [1,2,3,4].shuffle  #=> [2,4,1,3]

[ show source ]

# File lib/more/facets/random.rb, line 185
    def shuffle
      dup.shuffle!
      #sort_by{Random.number}
    end
shuffle!()

As with shuffle but modifies the array in place. The algorithm used here is known as a Fisher-Yates shuffle. 

  a = [1,2,3,4]
  a.shuffle!
  a  #=> [2,4,1,3]

CREDIT Niel Spring

[ show source ]

# File lib/more/facets/random.rb, line 199
    def shuffle!
      s = size
      each_index do |j|
        i = Random.number(s-j)
        #self[j], self[j+i] = self[j+i], self[j]
        tmp = self[j]
        self[j] = self[j+i]
        self[j+i] = tmp
      end
      self
    end