[Timlinux] The role of Python nonlocal and global

1. Execute code

The following examples are executed by executing the following code, which requires the following execution code to be placed behind the instance code.

A = Outer_func ()
= Outer_func ()
Print ("Call B ()") b () b () b ()

2. nonlocal not used

def Outer_func ():     = 3    def  Inner_func ():        + = 1        print("count" , Count)     return Inner_func # output>>> #     Count + = 1#unboundlocalerror:local variable ' count ' referenced before assignment 

3. Using nonlocal

defOuter_func (): Count= 3defInner_func (): nonlocal count Count+ = 1Print("Count", Count)returnInner_func#output>>>#Call A ()#Count 4#Count 5#Count 6#Call B ()#Count 4#Count 5#Count 6

4. Using Global (Error)

def Outer_func ():     = 3    def  Inner_func ():        Global  count        + = 1        print( " Count " , Count)     return Inner_func # output>>> #      Count + = 1#  nameerror:name ' count ' is not defined

5. Using Global (Success)

Count = 3defOuter_func ():defInner_func ():GlobalCount Count+ = 1Print("Count", Count)returnInner_func#output>>>#Call A ()#Count 4#Count 5#Count 6#Call B ()#Count 7#Count 8#Count 9

[Timlinux] The role of Python nonlocal and global