Local and Global Variables in Python

 

Local and Global Variables in Python

 

When we declare a variable inside a function , it becomes a local variable . A local variable is a variable whose scope is limited only to that function where it has been created .

 

This means that the local variable value is available only within that function and not outside that function .

 

Example

variable 'a' is declared inside the myfunction() function

and hence this is available within that function .

 

Once the code logic comes out of the scope of the function , the variable in use over here that is 'a' is removed from the memory and it is no more available in the memory .

 

Following is an example of a code, which uses a local variable within a function , and when the local variable defined within a function is tried to be accessed outside the scope of the function , an error is produced .

 

# local variable within a function

def myfunction():

a = 1                        # here , a is a local variable

a = a + 1                   # increment local variable value

print(a)

myfunction()

print(a)                              # error , not available

 

 

One can observe from the last statement that is print(a) we are displaying the value of variable 'a' outside the scope of the function . This statement raises an error with a message name 'a' not defined .

 

 

When a variable is declared above a function, the value becomes a global variable. Such variables are available to all the functions which are written after it, If such a variable is declared above a function, then such a variable becomes a global variable. Such type of variables is available to all the functions which are written after it. One can consider a sample piece of code for understanding the same :

 

Example

# global variable example

var_a = 1                                           # this is a global variable

def somefunction():

var_b = 2                                   # this is a local variable

print(' variable a = ',var_a  # call to display global var val

print(' variable b = ,'var_b) # call to display local variable's

somefunction()                                 # call to the function

print(var_a)      # the value is accessible outside function

print(var_b)      # the value is not accessible outside function

rather its value was only obtained when the call to

function 'somefunction' got executed.