Ruby 2.4 adds Enumerable#uniq & Enumerable::Lazy#uniq
In Ruby, we commonly use uniq method on an array to fetch the collection of all unique elements. But there may be cases where we might need elements in a hash by virtue of uniqueness of its values. Let's consider an example of countries that have hosted the Olympics. We only want to know when was the first time a country hosted it. 1 2# given object 3{ 1896 => 'Athens', 4 1900 => 'Paris', 5 1904 =
Ruby 2.4 implements Enumerable#sum
It is a common use case to calculate sum of the elements of an array or values from a hash. 1 2[1, 2, 3, 4] => 10 3 4{a: 1, b: 6, c: -3} => 4 5 Copy 1 2> [1, 2, 3, 4].sum 3 #=> 10 4 5> {a: 1, b: 6, c: -3}.sum{ |k, v| v**2 } 6 #=> 46 7 8> ['foo', 'bar'].sum # concatenation of strings 9 #=> "foobar" 10 11> [[1], ['abc'], [6, 'qwe']].sum # concatenation of arrays 12 #=> [1, "abc", 6, "qwe"] 13 Copy U
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