函数的进阶

def chi(quality_food, junk_food):
    print("我要吃", quality_food, junk_food)
chi("??饭", "??饭")  # "??饭"传递给quality_food  "??饭"传递给junk_food
按照位置传

def chi(*food):
    print("我要吃", food)
chi("??饭", "??饭")
结果:
我要吃 ('??饭', '??饭') # 多个参数传递进去. 收到的内容是元组tuple

def chi(*food, a, b):
    print("我要吃", food, a, b)
chi("??饭", "??饭", "??", "茄?")

Traceback (most recent call last):
    File "/Users/sylar/PycharmProjects/oldboy/fun.py", line 95, in <module>
    chi("??饭", "??饭", "??", "茄?")
TypeError: chi() missing 2 required keyword-only arguments: 'a' and 'b'

def chi(*food, a, b):
     print("我要吃", food, a, b)
chi("??饭", "??饭", a="??", b="茄?") # 必须?关键字参数来指定

def chi(a, b, *food):
    print("我要吃", a, b, food)
chi("??饭", "??饭", "馒头", "?条") # 前两个参数?位置参数来接收, 后?的参数?
动态参数接收

def chi(a, b, c='馒头', *food):
    print(a, b, c, food)

chi("?蕉", "菠萝") # ?蕉 菠萝 馒头 (). 默认值?效
chi("?蕉", "菠萝", "葫芦娃") # ?蕉 菠萝 葫芦娃 () 默认值不?效
chi("?蕉", "菠萝", "葫芦娃", "?罩") # ?蕉 菠萝 葫芦娃 ('?罩',) 默认值不?效

def chi(a, b, *food, c="娃哈哈"):
    print(a, b, food, c)
chi("?蕉", "菠萝") # ?蕉 菠萝 () 娃哈哈 默认值?效
chi("?蕉", "菠萝", "葫芦娃") # ?蕉 菠萝 ('葫芦娃',) 娃哈哈 默认值?效
chi("?蕉", "菠萝", "葫芦娃", "?罩") # ?蕉 菠萝 ('葫芦娃', '?罩') 娃哈哈 默
认值?效

def func(**kwargs):
    print(kwargs)
func(a=1, b=2, c=3)
func(a=1, b=2)
结果:
{'a': 1, 'b': 2, 'c': 3}
{'a': 1, 'b': 2}

def func(a, b, c, d):
    print(a, b, c, d)

# 关键字参数必须在位置参数后?, 否则参数会混乱
func(1, 2, c=3, 4)

def func(*args, **kwargs):
    print(args, kwargs)
func("麻花藤","?晕",wtf="胡辣汤")

def fun(*args):
    print(args)

lst = [1, 4, 7]
fun(lst[0], lst[1], lst[2])

fun(*lst) # 可以使?*把?个列表按顺序打散
s = "?妾做不到"
fun(*s) # 字符串也可以打散, (可迭代对象)

def fun(**kwargs):
    print(kwargs)
dic = {'a':1, 'b':2}
fun(**dic)

def chi(food, drink):
 """
 这?是函数的注释, 先写?下当前这个函数是?什么的, ?如我这个函数就是?个吃
 :param :param food: 参数food是什么意思
 :param :param drink: 参数drink是什么意思
 :return :return: 返回的是什么东东
 """
 print(food, drink)
 return "very good"

def fun():
    a = 10
    print(a)
fun()
print(a) # a不存在了已经..

a = 10
def func():
    a = 20
    print(a)
func() # 20

a = 10
def func():
    a = 40
    b = 20
    def abc():
    print("哈哈")
    print(a, b) # 这?使?的是局部作?域
    print(globals()) # 打印全局作?域中的内容
    print(locals()) # 打印局部作?域中的内容
func()

def fun1():
    print(111)
 
def fun2():
    print(222)
    fun1()

fun2()
print(111)
# 函数的嵌套
def fun2():
    print(222)
    def fun3():
    　　print(666)
    print(444)
    fun3()
    print(888)
print(33)
fun2()
print(555)

a = 100
def func():
    global a # 加了个global表示不再局部创建这个变量了. ?是直接使?全局的a
    a = 28
    print(a)
func()
print(a)

lst = ["麻花藤", "刘嘉玲", "詹姆斯"]
def func():
    lst.append("?云云") # 对于可变数据类型可以直接进?访问. 但是不能改地址. 说?
了. 不能赋值
    print(lst)
func()
print(lst)

a = 10
def func1():
    a = 20
    def func2():
    nonlocal a
    a = 30
    print(a)
    func2()
    print(a)
func1()
结果:
加了nonlocal
30
30
不加nonlocal
30
20

a = 1
def fun_1():
    a = 2
    def fun_2():
    nonlocal a
    a = 3
    def fun_3():
    a = 4
    print(a)
    print(a)
    fun_3()
    print(a)
    print(a)
    fun_2()
    print(a)
print(a)
fun_1()
print(a)