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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:
25
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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