Interpretation of local variables and global variables in Python

num = 5

def func ():

num + = 1

Print (num)

Print (num)

Output:unboundlocalerror:local variable ' num ' referenced before assignment

Translation: Local variable error: the variable "num" is not defined and is applied. This proves once again that a local variable is defined, not a global "num" that is used

Summary: When a variable already outside the function body has been defined as a global variable, it is re-assigned in the function body again, and then the variable is defined as a local variable in the function body, only in the function body will be effective. Restores a state that was not previously defined in the function body when it was outside the body of the function.

def func ():

num = 10

Print (num)

Func ()

Print (num)

Output:nameerror:name ' num ' is not defined

Name error: Variable num is not defined

This means that NUM is defined as a local variable and is valid only within the function body.

num = 100

def func ()

x = num +100

Print (x)

Output: 200

This means that num is used as a global variable.

Summary: See the program Yourself

If you want to define a global variable within a function body, you can define it with Globa, as follows:

num = 100

def func ():

Global num

num = 200

Print (num)

Func ()

Print (num)

Output: 200

Output: 200

This indicates that NUM is used as a global variable.

Interpretation of local variables and global variables in Python