Python Global Keyword

Global keyword in Python

Global keyword is a keyword that allows a user to modify a variable outside of the current scope. It is used to create global variables from a non-global scope i.e inside a function. Global keyword is used inside a function only when we want to do assignments or when we want to change a variable. Global is not needed for printing and accessing.

Rules of global keyword:

Use of global keyword:To access a global variable inside a function there is no need to use global keyword.Example 1:

 # Python program showing no need to
# use global keyword for accessing
# a global value
  
# global variable
a =15
b =10
  
# function to perform addition
defadd():
    c =a +b
    print(c)
  
# calling a function
add()

Output:

If we need to assign a new value to a global variable then we can do that by declaring the variable as global.Code 2: Without global keyword

 # Python program showing to modify
# a global value without using global
# keyword
  
a =15
  
# function to change a global value
defchange():
  
    # increment value of a by 5
    a =a +5
    print(a)
  
change()

Output:

 
UnboundLocalError: local variable 'a' referenced before assignment

This output is an error because we are trying to assign a value to a variable in an outer scope. This can be done with the use of global variable.Code 3 : With global keyword

❮ Python Keywords

Example

Declare a global variable inside a function, and use it outside the function:

 
#create a function:
def myfunction():
  global x
  x = 
    "hello"

#execute the function:
myfunction()

#x should now 
    be global, and accessible in the global scope.
print(x)

Definition and Usage

The global keyword is used to create global variables from a no-global scope, e.g. inside a function.

❮ Python Keywords

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