函数的进阶

def chi(food , junk_food):
    print("我要吃",food , junk_food)
chi("大米饭" , "小米饭")  #"大米饭"传递给food   "小米饭"传递给junk_food按照位置传

def chi(*food)
    print("我要吃" , food)
chi("大米饭" , "小米饭")

结果:
我要吃("大米饭" , "小米饭")     # 多个参数传递进去,接收到的内容是元组tuple

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

chi("大米饭", "小米饭", "黄瓜", "茄子") 

Traceback (most recent call last):  
    File "/Users/sylar/PycharmProjects/oldboy/fun.py", line 95, in <module>    
    chi("大米饭", "小米饭", "黄瓜", "茄子") 
TypeError: chi() missing 2 required keyword-only arguments: ‘a‘ and ‘b‘     

def chi(*food, a, b):    
    print("我要吃", food, a, b) 
chi("大米饭", "小米饭", a="黄瓜", b="茄子")   # 必须用关键字参数来指定 

def chi(a, b, c=‘馒头‘, *food):    
    print(a, b, c, food) 
chi("香蕉", "菠萝")  # 香蕉 菠萝 馒头 (). 默认值生效 
chi("香蕉", "菠萝", "葫芦娃")  # 香蕉 菠萝 葫芦娃 ()    默认值不生效 
chi("香蕉", "菠萝", "葫芦娃", "口罩")    # 香蕉 菠萝 葫芦娃 (‘口罩‘,) 默认值不生效 

def chi(a, b, *food, c="娃哈哈"):    
    print(a, b, food, c) 
chi("香蕉", "菠萝")  # 香蕉 菠萝 () 娃哈哈   默认值生效 
chi("香蕉", "菠萝", "葫芦娃")  # 香蕉 菠萝 (‘葫芦娃‘,) 娃哈哈    默认值生效 
chi("香蕉", "菠萝", "葫芦娃", "口罩")    # 香蕉 菠萝 (‘葫芦娃‘, ‘口罩‘) 娃哈哈  默 认值生效 

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面, 否则参数会混乱 
func(1, 2, c=3, 4)

def func(*args, **kwargs):    
    print(args, kwargs) 

func("麻花藤","马晕",wtf="胡辣汤") 

def fun(*args):    
    print(args)

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

fun(*lst)   # 可以使用*把一个列表按顺序打散 
s = "臣妾做不到" 
fun(*s)     # 字符串也可以打散, (可迭代对象) 

def chi(food, drink):    
"""   
这里是函数的注释 , 先写一下当前这个函数是干什么的 , 比如我这个函数就是一个吃    
:param food: 参数 food 是什么意思    
:param drink: 参数 drink 是什么意思    
:return: 返回的是什么东东    
"""    
print(food, drink)    
return "very good"

a = 10 
def func():    
    a = 40    
    b = 20    
    def abc():        
        print("哈哈")    
    print(a, b)     # 这里使用的是局部作用域    
    print(globals())    # 打印全局作用域中的内容    
    print(locals())     # 打印局部作用域中的内容 

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. 而是直接使用全局的a    
    a = 28    
    print(a) 
func() 
print(a)

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)