Python Global and Local Variable
Local and Global variable
All variables in a program may not be accessible at all locations in that program. This depends on where you have declared a variable.
The scope of a variable determines the portion of the program where you can access a particular identifier. There are two basic scopes of variables in Python.
- Local Variable
- Global Variable
Local Variable
Variables declared inside a function body is known as Local
Variable. These have local access thus these variables cannot be
accessed outside the function body in which they are declared.
Example:
def abc():
#local Variable
a=200
print ("value of a is",a)
abc()
Output:
value of a is 200
Global Variable
Variable defined outside the function is called Global Variable. The global variable is accessed all over the program thus a global variable
has the widest accessibility.
Example:
#global Variable
b=100
def abc():
#local Variable
a=200
print ("Value of a is",a)
print ("Value of b is",b)
abc()
print ("Value of b is",b)
Output:
Value of a is 200
Value of b is 100
Value of b is 100
Global Keyword
In Python, the global keyword allows you to modify the variable
outside of the current scope. It is used to create a global variable
and make changes to the variable in a local context.
- When we create a variable inside a function, it’s local by default.
- When we define a variable outside of a function, it’s global by default. You don’t have to use the global keyword.
- We use global keyword to read and write a global variable inside a function.
- Use of global keyword outside a function has no effect.
Example:
def abc():
#local Variable
a=200
#global Variable using global keyword
global b
b = 100
print ("Value of a is",a)
print ("Value of b is",b)
abc()
print ("Value of b is",b)
Output:
Value of a is 200
Value of b is 100
Value of b is 100