python - function 11, namespace

Three namespaces 
1. Built-in namespace: 
    The name that comes with the python interpreter, such as: print, sum, max 
    This space is formed when the interpreter starts

2. Global namespace: 
     This space is generated when the python program is executed. 
     Write code at the top of each line

a=10
def foo():
    print(a)
foo()

View Code

3: Local namespace 
    The name defined inside the 
    function takes effect when the function is called

# def foo2(a,b):
#     c=1
#     print(a,b,c)
# foo2(10,9)

View Code

Loading order of the three: built-in -> global -> local 

value order of the three: local -> global -> built-in

a=10
def foo1():
    a=20
    print(a)
foo1()
#Because there is a value locally, it is printed as 20


b=10
def foo2():
    #b=20
    print(a)
foo2()
#When the local has no value, it will find the global so it is printed as 10



#sum=10
def foo3():
    #sum=20
    print(sum)
foo3()
#When the local has no value and the global has no value, it will find the built-in

View Code