python global and local variables

First, what is a global variable? local variables?

Answer: A variable that takes effect globally is called a global variable, and a variable defined in a subprogram is called a local variable

When a global variable has the same name as a local variable, in the subprogram where the local variable is defined, the local variable takes effect, and the global variable takes effect elsewhere.

#-*-coding:utf-8-*- 
name = "hello" #global variable 
def change_name(): 
    x= 1 #local variable 
name = "hello" print ( "changename",name) change_name() #output is the local variable print name #The output is the global variable
 

 Second, the keyword global global variable is redeclared, and the output is the variable after redeclaration

#-*-coding:utf-8-*-
name = "hello" #global variable
def change_name():
    x=1#local variable
    global name
    name = "hello"
    print ("changename",name)
change_name()
print name #After adding global, the global variable is changed, and the output is hello

 three,

#If the content of the function has no global keyword
# - has declared local variables
NAME = ["n","l"]
# def qupengfei():
#      NAME = "myself"
#      print('want', NAME)
# qupengfei()
- no declaration of local variables
def qupengfei():
    NAME.append("d")
    print('want', NAME)
qupengfei()

 

## If the content of the function has the global keyword
# - has declared local variables
NAME = ["n","l"]
def qupengfei():
     global  NAME
     NAME = "myself"
     print('want', NAME)
qupengfei()

 Exercise: Please output the print content: Huang Wei
Liu Yang Liu
Yang
Hu Zhi Hua
Huang Wei

def huangwei():
    name = "Huang Wei"
    print(name)
    def liuyang():
        name = "Liu Yang"
        print(name)
        def nulige():
            name = 'Hu Index Flower'
            print(name)
        print(name)
        nulige ()
    liuyang()
    print(name)
huangwei()

 Exercise 2

name = "gang"
def weihou():
    name = "chen"
    def weiweiho():
        global name
        name ="leng"
    weiweiho()
    print name

print name
weihou()
print name

 The output is: gang
chen
leng