CODEWITHSUNDEEP
ruby
Junan Chakma
Junan Chakma

Reputation: 651

Removing duplicate array elements

In [[1,2],[2,1],[8,9],[12,12]], the first two elements are same. I want to get an output like this: [[8,9],[12,12]].

In:

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

I want to get an output like this:

[[1, 1], [2, 2], [3, 3]]

Upvotes: 0

Views: 80

Answers (2)

dwenzel
dwenzel

Reputation: 1434

Ruby does have a #uniq method, but that removes any duplicates but KEEPS one of them. So that will not work in your case, since it appears that you're looking to remove ALL elements that have duplicates.

Here's a solution that should do the trick:

def remove_dups(array)
  new_array = []
  # first, sort each element
  start_array = array.map{|e| e.sort}
  start_array.each_with_index do |sub_array, idx|
    temp_array = start_array.dup
    temp_array.delete_at(idx)
    # after deleting the element, check to see if the array still includes the element
    new_array << sub_array unless temp_array.include?(sub_array)
  end
new_array
end

p remove_dups([[1,2],[2,1],[8,9],[12,12]])
#=> [[8, 9], [12, 12]]
p remove_dups([1,2,3].product([1,2,3]))
#=> [[1, 1], [2, 2], [3, 3]]

Upvotes: 1

shivam
shivam

Reputation: 16506

To get unique output irrespective of individual Array's arrangement, do this:

[1,2,3].product([1,2,3]).map(&:sort).uniq
#  => [[1, 1], [1, 2], [1, 3], [2, 2], [2, 3], [3, 3]]

If you require output with only repetitive values, do this:

[1,2,3].product([1,2,3]).map {|k,v| [k,v] if k == v}.compact
# => [[1, 1], [2, 2], [3, 3]]

Upvotes: 2

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