Scope of the Python variable

Variable scope:

In general, variables defined in the function body are called global variables, and variables defined in the function body are called local variables.

When a function is called, it usually reads its own local variable before reading the global variable.

You can access global variables within a function, but to modify global variables, you need certain conditions:

If the global variable is a mutable data type , you can modify it directly:

DIC = {0:0, 1:1, 2:2}def F ():    dic[3] = 3f () print dic>>{0:0, 1:1, 2:2, 3:3}

If the global variable is an immutable data type , or you want to re-assign a value to a mutable data type :

You need to use the Global keyword

　　

LST = [1,2,3]def f ():    lst = ' hehe '    print lstf () print lst>> ' hehe ' >> [[+]

LST = [1,2,3]def f ():    global lst    lst = ' hehe '    print lstf () print lst>> ' hehe ' >> ' hehe '

That is, lists and dictionaries can be modified directly within the function;

To re-assign a value, you need to use the Global keyword. (Immutable data types such as String, Integer, tuple, modify = = Assignment)

Scope of the Python variable