Python | Accessing variable value from code scope

Sometimes, we just need to access a variable other than the usual way of accessing by it's name. There are many method by which a variable can be accessed from the code scope. These are by default dictionaries that are created and which keep the variable values as dictionary key-value pair. Let's talk about some of these functions. 

Method #1 : Using locals() 

This is a function that stores the values of all variables in local scope of function if in a function or of global scope if outside. 

# Python3 code to demonstrate working of
# Accessing variable value from code scope
# using locals

# initialize variable
test_var = "gfg is best"

# printing original variable
print("The original variable : " + str(test_var))

# Accessing variable value from code scope
# using locals
res = locals()['test_var']

# printing result
print("Variable accessed using dictionary : " + str(res))

The original variable : gfg is best
Variable accessed using dictionary : gfg is best

Method #2: Using globals() This is yet another function that maintains a dictionary of variables of global scope. 

# Python3 code to demonstrate working of
# Accessing variable value from code scope
# using globals

# initialize variable
test_var = "gfg is best"

# printing original variable
print("The original variable : " + str(test_var))

# Accessing variable value from code scope
# using globals
res = globals()['test_var']

# printing result
print("Variable accessed using dictionary : " + str(res))

The original variable : gfg is best
Variable accessed using dictionary : gfg is best

Method #3: Using a class

1. Define a class MyClass with a class-level variable my_var set to the desired value.
2. Define a function func2 that prints the value of MyClass.my_var.
3. Call func2 to print the value of MyClass.my_var.

class MyClass:
    my_var = 'gfg is best'


def func2():
    print(MyClass.my_var)


func2()  # Output: gfg is best

gfg is best

Time complexity: O(1)
Auxiliary Space: O(1)

Method 4: using the built-in function vars(). 

Steps:

1. Initialize a variable test_var with a string value.
2. Print the original variable using the print() function.
3. Use the vars() function to access the variable value from code scope and assign it to a new variable res.
4. Print the result.

# initialize variable
test_var = "gfg is best"

# printing original variable
print("The original variable : " + str(test_var))

# Accessing variable value from code scope
# using vars
res = vars()['test_var']

# printing result
print("Variable accessed using dictionary : " + str(res))

The original variable : gfg is best
Variable accessed using dictionary : gfg is best

Time complexity of this program is O(1)

Auxiliary space required is O(1).