Cmbinations in Array

rubyonrails-talk
1

Hi, I want to find the combination of array elements

like for example a = [1,2,3,4] the combinations are [1,2,3,4] [1,3,4,2] [1,2,3] etc..

If anybody knows plz reply me

2

Do you want to know the number of possible combinations or the combinations themselves?

3

Pragash Mr. wrote:

Hi, I want to find the combination of array elements

like for example a = [1,2,3,4] the combinations are [1,2,3,4] [1,3,4,2] [1,2,3] etc..

If anybody knows plz reply me

Think this works,

def combinations(array)   return if array ==   return [array, ] if array.length == 1

  # split [1,2,3] => [1], [2,3]   left, right = array[0..0], array[1..-1]   rtn =

  combinations(right).each do |r_array|     rtn << r_array     rtn << left + r_array   end

  return rtn end

combinations([1])

=> [[1]]

combinations([1])

=> [[1], ]

combinations([1,2])

=> [[2], [1, 2], , [1]]

combinations([1,2,3])

=> [[3], [1, 3], [2, 3], [1, 2, 3], , [1], [2], [1, 2]]

enjoy. http://www.workingwithrails.com/person/12394-matthew-rudy-jacobs