第 018讲：函数：灵活即强大（关键字函数，默认函数，收集函数）

数：

0.形参和实参：

>>> def saysomething(name, words): \name是形参； Jenny是实参
print(name + '->' + words)

>>> saysomething("jenny", "happy")
jenny->heppy

1.关键字函数：

>>> def saysomething(name, words):
print(name + '->' + words)

>>> saysomething(words = "happy", name = "jenny")
jenny->happy

2. 默认函数：

>>> def saysomething(name = "jenny", words = "happy"):
print(name + '->' + words)

>>> saysomething()
jenny->happy

>>> def saysomething(name, words):
print(name="jenny" + '->' + words="happy") \不能在print里面赋实参

SyntaxError: invalid syntax

3. 收集函数（可变参数）：

>>> def test(* paratest):
print("有 %d 个参数" % len(paratest)) \  不明白
print("第二个参数是：", paratest[1])

>>> test('j','e','n','n','y')
有 5 个参数
第二个参数是： e