Skip to content
Related Articles

Related Articles

Improve Article

Python – Convert Key-Value list Dictionary to List of Lists

  • Last Updated : 22 Apr, 2020

Sometimes, while working with Python dictionary, we can have a problem in which we need to perform the flattening a key value pair of dictionary to a list and convert to lists of list. This can have applications in domains in which we have data. Lets discuss certain ways in which this task can be performed.

Method #1 : Using loop + items()
This brute force way in which we can perform this task. In this, we loop through all the pairs and extract list value elements using items() and render in a new list.




# Python3 code to demonstrate working of 
# Convert Key-Value list Dictionary to Lists of List
# Using loop + items()
  
# initializing Dictionary
test_dict = {'gfg' : [1, 3, 4], 'is' : [7, 6], 'best' : [4, 5]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Convert Key-Value list Dictionary to Lists of List
# Using loop + items()
res = []
for key, val in test_dict.items():
    res.append([key] + val)
  
# printing result 
print("The converted list is : " + str(res)) 
Output :

The original dictionary is : {‘gfg’: [1, 3, 4], ‘is’: [7, 6], ‘best’: [4, 5]}
The converted list is : [[‘gfg’, 1, 3, 4], [‘is’, 7, 6], [‘best’, 4, 5]]

 



Method #2 : Using list comprehension
This task can also be performed using list comprehension. In this, we perform the task similar to above method just in one-liner shorter way.




# Python3 code to demonstrate working of 
# Convert Key-Value list Dictionary to Lists of List
# Using list comprehension
  
# initializing Dictionary
test_dict = {'gfg' : [1, 3, 4], 'is' : [7, 6], 'best' : [4, 5]}
  
# printing original dictionary
print("The original dictionary is : " + str(test_dict))
  
# Convert Key-Value list Dictionary to Lists of List
# Using list comprehension
res = [[key] + val for key, val in test_dict.items()]
  
# printing result 
print("The converted list is : " + str(res)) 
Output :

The original dictionary is : {‘gfg’: [1, 3, 4], ‘is’: [7, 6], ‘best’: [4, 5]}
The converted list is : [[‘gfg’, 1, 3, 4], [‘is’, 7, 6], [‘best’, 4, 5]]

 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. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course




My Personal Notes arrow_drop_up
Recommended Articles
Page :