Ruby 2.4 adds Enumerable#uniq & Enumerable::Lazy#uniq

In Ruby, we commonly use uniq method on an array to fetch the collection ofall unique elements. But there may be cases where we might need elements in ahash by virtue of uniqueness of its values. Let's consider an example of countries that have hosted the Olympics. We onlywant to know when was the first time a country hosted it. # given object{ 1896 => 'Athens', 1900 => 'Paris', 1904 => 'Chicago',