# creating an empty hash

h = <[]>        # => <[]>
h["a"]: 1         # => <["a" => 1]>
h["test"]: 2.4  # => <["a" => 1, "test" => 2.4]>
h[3]: "Hello"   # => <["a" => 1, "test" => 2.4, 3 => "Hello"]>

# creating a hash with the constructor
h = Hash new           # => <[]>