Function (4)

Function object:

1 , can be assigned

f=func

print(f,func)

f()

2 , can be used as the function as an argument to another function

def foo(x):

    # print(x)

    x()

3 , can be used as additional function as a return value of the function

def foo(x):

    return x

res=foo(func)

print(res)

res()

4 , elements of the container can be used as a type of

l = [function,]

# print(l)

l[0]()

 
name = { ' k1 ' : func}

print (say)

I say [ ' k1 ' ] ()

Nested functions:

1 , nested function calls: calling a function of the process and call other functions

def max2(x,y):

    if x > y:

        return x

    else:

        return y

def max4(a,b,c,d):

    res1=max2(a,b)

    res2=max2(res1,c)

    res3=max2(res2,d)

    return res3


res = max4 (1,2,3,4 )

print(res)

2 , the nested function definition : to define other functions within a function

def f1():

    def f2():

        pass

Closure function:

Closure function = namespace and scope + recursive function + function object

The core point: the name of the relationship is to find the function definition stage prevail

" Closed " function refers to the function is built-in functions

" Pack " function refers to the function of the outer layer contains a reference to the name of the function scope

Closure function: namespace application and scope + nested functions

def f1():
    x = 333
    def f2():
        print(x)
    f2()
x=11111
def bar():
    x=44
    f1 ()
def foo():
    x=2222
    bar()
foo()

Closure function: function objects

def f1():
    x = 333
    def f2():
        print(x)
    return f2
f=f1()
def foo():
    x=5555
    f()
foo()

Two kinds of transmission parameters as a function of the way the body

Way: the parameter defines the function body directly molded required parameters

def f2(x):
    print(x)
f2(1)
f2(2)
f2(3)

Second way: nested call

def f1(x):
    x=3
    def f2():
        print(x)
    return f2
x=f1(3)
print(x)

x()

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