Python - Convert Lists of List to Dictionary

Sometimes, while working with Python records, we can have problem in which we have data in form of Lists of list and we need to allocate certain elements as keys and certain as values to form a dictionary. This type of application can occur in data domains. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop
This is brute way in which we perform this task. In this, we iterate through the lists forming key value pairs according to required slicing.

# Python3 code to demonstrate working of  
# Convert Lists of List to Dictionary 
# Using loop 
  
# initializing list 
test_list = [['a', 'b', 1, 2], ['c', 'd', 3, 4], ['e', 'f', 5, 6]] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Convert Lists of List to Dictionary 
# Using loop 
res = dict() 
for sub in test_list: 
    res[tuple(sub[:2])] = tuple(sub[2:]) 
      
# printing result  
print("The mapped Dictionary : " + str(res))  

Output :

The original list is : [[‘a’, ‘b’, 1, 2], [‘c’, ‘d’, 3, 4], [‘e’, ‘f’, 5, 6]]
The mapped Dictionary : {(‘c’, ‘d’): (3, 4), (‘e’, ‘f’): (5, 6), (‘a’, ‘b’): (1, 2)}

Method #2 : Using dictionary comprehension
This is yet another way in which this task can be performed. This is similar to above method, just a one liner alternative.

# Python3 code to demonstrate working of  
# Convert Lists of List to Dictionary 
# Using dictionary comprehension 
  
# initializing list 
test_list = [['a', 'b', 1, 2], ['c', 'd', 3, 4], ['e', 'f', 5, 6]] 
  
# printing original list 
print("The original list is : " + str(test_list)) 
  
# Convert Lists of List to Dictionary 
# Using dictionary comprehension 
res = {tuple(sub[:2]): tuple(sub[2:]) for sub in test_list} 
      
# printing result  
print("The mapped Dictionary : " + str(res))  

Output :

The original list is : [[‘a’, ‘b’, 1, 2], [‘c’, ‘d’, 3, 4], [‘e’, ‘f’, 5, 6]]
The mapped Dictionary : {(‘c’, ‘d’): (3, 4), (‘e’, ‘f’): (5, 6), (‘a’, ‘b’): (1, 2)}

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course.

My Personal Notes

Python – Convert Lists of List to Dictionary

Recommended Posts: