# #定义阶段
# def foo():
#     print(‘from foo‘)
#     bar()
#
# def bar():
#     print(‘from bar‘)
#
# #调用阶段
# foo()


#定义阶段:只检测语法，不执行代码
# def func():
#    if 1>2
#        print(‘hahahahahahah‘)


def func(): #语法没问题，逻辑有问题，引用一个不存在的变量名

def foo(x,y):
    print(x)
    print(y)
#按位置定义的形参,必须被传值，多一个不行，少一个也不行，按位置对应传入
 foo(1,2)

def foo(x,y):
     print(x)
     print(y)
foo(y=10,x=1)
 foo(y=10,x=1) #关键字参数可以不用像位置实参一样与形参一一对应，需要指名道姓地传值

def func(x,y=10):   #形参中给了默认值，实参中可以不用传值，那么会按照默认值运行
     print(x)             #传值的话就会按传入的值运行    
     print(y)


 func(1,20)
 func(1)

def func(x,y,*args): #x=1,y=2,args=(3,4,5,6)#*号接收x,y以外的参数，以元组的形式赋值给args
     print(x,y)
     print(args)

 func(1,2,3,4,5,6)




 def func(x,y,*args):  #args=(3,4,5,6)
     print(x,y)
     print(args)

 func(1,2,*(3,4,5,6)) #*号后拆开即为foo(1,2,3,4,5,6)


 def func(x,y,z):
     print(x,y,z)

 func(1,*(2,3)) #func(1,2,3)#同上
 func(*(2,3)) #func(2,3)



 def func(x,y,**kwargs): #x=1,y=2,kwargs={‘a‘:1,‘b‘:3,‘z‘:3}#**用来接收关键字参数，并以字典形式赋值给kwargs
     print(x,y)
     print(kwargs)

 func(1,y=2,z=3,a=1,b=3)#关键字参数必须放在位置参数后


 def func(x,y,**kwargs): #x=1,y=2,**kwargs=**{‘a‘:1,‘b‘:3,‘z‘:3}
     print(x,y)
     print(kwargs)

 func(1,y=2,**{‘a‘:1,‘b‘:3,‘z‘:3}) #**拆开即为func(1,y=2,z=3,b=3,a=1)


 def func(x,y=1,z=1):
     print(x,y,z)

 func(**{‘y‘:2,‘x‘:1,‘z‘:3}) #


 def wrapper(*args,**kwargs): #可以接受任意形式，任意长度的参数
     print(args)
     print(kwargs)


 wrapper(1,2,3,3,3,3,3,x=1,y=2,z=3)

 def max2(x,y):
     if x > y:
         return x
     else:
         return y

 def max4(a,b,c,d):
     res1=max2(a,b) #23
     res2=max2(res1,c) #23
     res3=max2(res2,d) #31
     return res3


 print(max4(11,23,-7,31))

def func():
    print(‘from func‘)

#可被引用
f=func

#可以当做函数的参数
def func():
    print(‘from func‘)
def foo(x):
    print(x)
    x()
foo(func)

#可以当做函数的返回值
def foo():
    print(‘from foo‘)
def bar():
    return foo
f=bar()
print(f)
print(foo)

x=0
def f1():
    x=1
    def f2():
        # x=2
        print(x)
    return f2
f=f1()
# print(f)
 f()



#可以当做容器类型的元素
def select():
    print(‘select function‘)
func_dic={
    ‘select‘:select,
}

# print(func_dic[‘select‘])
# func_dic[‘select‘]()






#
# def select():
#     print(‘select func‘)
#
# def delete():
#     print(‘delete func‘)
#
# def change():
#     print(‘change func‘)
#
# def add():
#     print(‘add func‘)
#
#
# while 1:
#     cmd=input(‘>>: ‘).strip()
#     if not cmd:continue
#     if cmd == ‘select‘:
#         select()
#     elif cmd == ‘delete‘:
#         delete()
#     elif cmd == ‘change‘:
#         change()
#     elif cmd == ‘add‘:
#         add()
#     else:
#         print(‘无效的命令‘)