Step two of the Python function

The essence of Function name

The function name is essentially the memory address of the function.

1, can be used as a value or variable reference

def func ():    print (111) print (func) #<function func at 0x00000218a911ab70>--function in memory address F = Func    # Pass it to the variable fprint (f)    #<function func at 0x00000279a5a6ab70>f ()         #111

2. Functions can be stored as elements of a container type

#将其当做容器存储在列表中def func1 ():    print (' func1 ') def func2 ():    print (' Func2 ') def func3 ():    print (' func3 ') lis = [ Func1, Func2, Func3]lis[0] ()      #func1lis [1] ()      #func2lis [2] ()      #func3

3, can be used as a function parameter and return value

#当做参数和返回值def func1 ():    print (' func1 ') def func (argv):    argv ()              return argv     #func1作为返回值f = func (func1)     #func1作为参数f () #输出func1func1

Summarize:

# 1. The memory address of the function name is--print (letter name). # 2, the function name can be assigned to other variables. # 3. The function name can be used as the element of the container class. # 4, the function name can be used as a function parameter. # 5, the function name can be used as the return value of the function. # Scientific Name: First Class objects (first-class object)
# In short: You can use the function name as a variable

Second, closed package

An inner function is defined in an outer function, and a temporary variable of the outer function is used in the inner function, and the return value of the outer function is a reference to the inner function. This makes up a closure (i.e., a reference to a variable of the inner layer function, the outer layer function (non-global)).

#闭包函数的基本用法def func ():    name = ' Eva '    def Inner ():        print (name)    return innerf = Func () f ()         #eva

Common properties for detecting closure functions: __closure__

#闭包函数 # Output If a cell is the closure function Def wrapper ():    name = ' is closure '    def inner ():        print (name)             #是闭包    inner ()    Print (inner.__closure__)    # (<cell at 0x000001945ce07588:str object at 0x000001945ce06b70>,) wrapper () # Non-closure function # Output If None is not the closure function name = ' not closures ' Def wrapper ():    def inner ():        print (name)             #不是闭包    inner ()    print (inner.__closure__)    #Nonewrapper ()

Step two of the Python function