Python dynamic parameters, namespaces and scopes, nesting of functions, global and nonlocal

I. Dynamic parameter transfer

1. Positional parameters Dynamic parameter transfer

def func (*args): * Indicates dynamic parameter transfer

* Here is the acceptance of the dynamic parameters of the positional parameter, the received tuple.

def fun (*args):    print (args) fun    (' aaa ', 3,5,6, ' CCC ') #  results (' AAA ', 3, 5, 6, ' CCC ')

　　

2. Dynamic parameter of keyword

def func (**kwargs):

function body (code block)

Func (n=7,m= "AA"):

* * Represents a dynamic parameter that receives a keyword argument, and a dictionary is received.

def fun (**kwargs):    print (Kwargs) fun (name= "Tom", age= "male", hobby= "female") # result {' name ': ' Tom ', ' age ': ' Male ', ' hobby ': ' Female '}

Order: Position parameter = = *arg (arguments) (parameter dynamic parameter) = = Default Value = = **kwargs (keyword argument)

The above parameters can be used in a casual combination

3. Comments on functions

def fun ():

"""

Comment that explains what this function is used for

”“”

Print (fun.__doc__) #document文档

def fun (A, A, b): "" "    Note that this function is used for what    :p Aram A:    :p Aram B:    : Return:" ""    returnfun (5,6) print (fun.__doc__)  #打印出函数的注释

　　

4. Receive All Parameters

def fun (*args,**kwargs): #无敌传参

Pass

*,** the position of the actual parameter is scattered

The *,** parameter position is an aggregation

def fun (*args,**kwargs):    print (Args,kwargs) li = [' R ', ' N ', ' G ', ' w ', ' I ', ' n ']dic = {' name ': ' Uzi ', ' age ': ' Male ', ' hobby ': ' ADC '}fun (*li,**dic) # results (' R ', ' N ', ' G ', ' w ', ' I ', ' n ') {' name ': ' Uzi ', ' age ': ' Male ', ' hobby ': ' ADC '}

　　

Second, namespace and scope

1. Global scope:

Global namespaces, built-in namespaces

2. Local scope:

Local namespaces

Globals () to view content in the global scope

Locals () view content in the current scope

A = 5  # global variable def fun ():    a = ten      #局部变量    print (Locals ()) Print (Globals ()) Fun ()

　　

Nesting of functions

Functions can be nested with each other

A = 1def fun ():    a = 5            def inner ():        a = ten           print (a)    inner ()    print (a) print (a) fun ()

　　

Global

1. You can introduce content from the global to the inside of the function

2. Create a variable at the global

(References are referenced when you want to change external values inside the function, and the global variable itself is unsafe and cannot be modified at will)

A = 1def fun ():    Global a    A + = 5    print (a)  #  6print (a)   #  1fun () print (a)   #  6

　　

Nonlocal

Look for the variable closest to him in the outer function.

A = 1def fun ():    a = 5    def inner ():        nonlocal a        A + = 5        print (a)    #    print (a)        # 5
   inner ()    print (a)        # 10print (a)            # 1fun () print (a)            # 1

　　

　　

Python dynamic parameters, namespaces and scopes, nesting of functions, global and nonlocal