How do I test if all items in an array are identical?

Question

You can use Enumerable#all? which returns true if the given block returns true for all the elements in the collection.

array.all? {|x| x == array[0]}

(If the array is empty, the block is never called, so doing array[0] is safe.)

class Array
  def same_values?
    self.uniq.length == 1
  end
end


[1, 1, 1, 1].same_values?
[1, 2, 3, 4].same_values?

What about this one? It returns false for an empty array though, you can change it to <= 1 and it will return true in that case. Depending on what you need.

I too like preferred answer best, short and sweet. If all elements were from the same Enumerable class, such as Numeric or String, one could use

def all_equal?(array) array.max == array.min end

I would use:

array = ["rabbits","rabbits","hares", nil, nil]
array.uniq.compact.length == 1

I used to use:

array.reduce { |x,y| x == y ? x : nil }

It may fail when array contains nil.