Ruby 2.0引入了关键字参数,**
的作用类似于*
,但用于关键字参数.它返回一个包含键/值对的散列.
对于此代码:
def foo(a, *b, **c)
[a, b, c]
end
下面是一个演示:
> foo 10
=> [10, [], {}]
> foo 10, 20, 30
=> [10, [20, 30], {}]
> foo 10, 20, 30, d: 40, e: 50
=> [10, [20, 30], {:d=>40, :e=>50}]
> foo 10, d: 40, e: 50
=> [10, [], {:d=>40, :e=>50}]