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TODAY I LEARNED

Ruby Double star (**)

def hello(a, *b, **c)
  return a, b, c
end

a is a regular parameter. *b will take all the parameters passed after the first one and put them in an array. **c will take any parameter given in the format key: value at the end of the method call.

See the following examples:

One parameter

hello(1)
# => [1, [], {}]

More than one parameter

hello(1, 2, 3, 4)
# => [1, [2, 3, 4], {}]

More than one parameter + hash-style parameters

hello(1, 2, 3, 4, a: 1, b: 2)
# => [1, [2, 3, 4], {:a=>1, :b=>2}]

Learned by Victor Velazquez on Mar 4, 2021

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