Skip to content

Courses
Tutorials
Practice
Contests

Python Tutorial
Interview Questions
Python Quiz
Python Glossary
Python Projects
Practice Python
Data Science With Python
Python Web Dev
DSA with Python
Python OOPs

Filter List of Python Dictionaries by Key in Python

Combine keys in a list of dictionaries in Python

Last Updated : 22 Feb, 2023

Comments

Improve

Suggest changes

Like Article

Like

Report

Sometimes, while working with Python dictionaries, we can have a problem in which we need to perform a merge of dictionaries in list with similar keys. This kind of problem can come in data optimization domains. Let’s discuss a way in which this task can be performed.

Input : test_list = [{‘a’: 6}, {‘b’: 2}, {‘a’: 9}, {‘b’: 7}]
Output : [{‘b’: 2, ‘a’: 6}, {‘b’: 7, ‘a’: 9}]

Input : test_list = [{‘a’: 8}, {‘a’: 2}, {‘a’: 3}]
Output : [{‘a’: 8}, {‘a’: 2}, {‘a’: 3}]

Method : loop + ** operator The combination of above functions can be used to solve this problem. In this, we use brute force to construct a new dictionary and add keys only if that is not added in current. The task of merging dictionaries is by unpacking the initial dictionaries using “**” operator, and then packing again with dictionary with no repeated key and new one, using the usual dictionary initialization construct {}.

Python3

   # Python3 code to demonstrate working of 
# Merge Similar Dictionaries in List
# Using loop + "**" operator
 
# initializing list
test_list = [{'gfg' : 1}, {'is' : 2}, {'best' : 3},
              {'gfg' : 5}, {'is' : 17}, {'best' : 14},
              {'gfg' : 7}, {'is' : 8}, {'best' : 10},]
 
# printing original list
print("The original list is : " + str(test_list))
 
# Merge Similar Dictionaries in List
# Using loop + "**" operator
res = [{}]
for sub in test_list:
    if list(sub)[0] not in res[-1]:
        res[-1] = {**res[-1], **sub}
    else:
        res.append(sub)
 
# printing result 
print("The merged dictionaries : " + str(res)) 
 
  

Output :

The original list is : [{‘gfg’: 1}, {‘is’: 2}, {‘best’: 3}, {‘gfg’: 5}, {‘is’: 17}, {‘best’: 14}, {‘gfg’: 7}, {‘is’: 8}, {‘best’: 10}] The merged dictionaries : [{‘best’: 3, ‘is’: 2, ‘gfg’: 1}, {‘best’: 14, ‘is’: 17, ‘gfg’: 5}, {‘best’: 10, ‘is’: 8, ‘gfg’: 7}]

Time complexity: O(n^2).
Auxiliary space: O(n).

Filter List of Python Dictionaries by Key in Python

manjeet_04

Improve

Article Tags :

Python
Python Programs
Python dictionary-programs

Practice Tags :

python

Similar Reads

Python - Common keys in list and dictionary

Given a dictionary and list, extract all the keys and list which are common. Input : test_dict = {"Gfg": 3, "is" : 5, "best" : 9, "for" : 0, "geeks" : 3}, test_list = ["Gfg", "best", "CS"] Output : ['Gfg', 'best'] Explanation : Gfg and best are present in both dictionary and List. Input : test_dict

Python - Add custom values key in List of dictionaries

The task of adding custom values as keys in a list of dictionaries involves inserting a new key-value pair into each dictionary within the list. In Python, dictionaries are mutable, meaning the key-value pairs can be modified or added easily. When working with a list of dictionaries, the goal is to

Python - Convert List to List of dictionaries

We are given a lists with key and value pair we need to convert the lists to List of dictionaries. For example we are given two list a=["name", "age", "city"] and b=[["Geeks", 25, "New York"], ["Geeks", 30, "Los Angeles"], ["Geeks", 22, "Chicago"]] we need to convert these keys and values list into

Dictionary keys as a list in Python

In Python, we will encounter some situations where we need to extract the keys from a dictionary as a list. In this article, we will explore various easy and efficient methods to achieve this. Using list() The simplest and most efficient way to convert dictionary keys to lists is by using a built-in

Filter List of Python Dictionaries by Key in Python

In Python, filtering a list of dictionaries based on a specific key is a common task when working with structured data. In this article, weâ€™ll explore different ways to filter a list of dictionaries by key from the most efficient to the least. Using List Comprehension List comprehension is a concise

Python - Convert List of Dictionaries to List of Lists

We are given list of dictionaries we need to convert it to list of lists. For example we are given a list of dictionaries a = [{'name': 'Geeks', 'age': 25}, {'name': 'Geeks', 'age': 30}] we need to convert it in list of list so that the output becomes[['Geeks',25],['Geeks;'30]]. Using List Comprehen

Iterating List of Python Dictionaries

Iteration of the list of dictionaries is a very common practice that every developer performs while encountering with dictionary data. In this article, we will explore how to iterate through a list of dictionaries. Iterating List Of Dictionaries in PythonBelow are some of the ways by which we can it

Get all Unique Keys from a List of Dictionaries - Python

Our task is to get all unique keys from a list of dictionaries and we are given a list where each element is a dictionary, we need to extract and return a list of keys that appear across all dictionaries. The result should contain each key only once regardless of how many times it appears. For examp

Python - Compare Dictionaries on certain Keys

Sometimes, while working with Python dictionaries, we can have a problem in which we need to compare dictionaries for equality on bases in selected keys. This kind of problem is common and has application in many domains. Lets discuss certain ways in which this task can be performed. Method #1 : Usi

Python - All combination Dictionary List

Given 2 lists, form all possible combination of dictionaries that can be formed by taking keys from list1 and values from list2. Input : test_list1 = ["Gfg", "is", "Best"], test_list2 = [4] Output : [{'Gfg': 4, 'is': 4, 'Best': 4}]Explanation : All combinations dictionary list extracted. Input : tes

Corporate & Communications Address:

A-143, 7th Floor, Sovereign Corporate Tower, Sector- 136, Noida, Uttar Pradesh (201305)

Registered Address:

K 061, Tower K, Gulshan Vivante Apartment, Sector 137, Noida, Gautam Buddh Nagar, Uttar Pradesh, 201305

Advertise with us

Company
About Us
Legal
Privacy Policy
In Media
Contact Us
Advertise with us
GFG Corporate Solution
Placement Training Program

Languages
Python
Java
C++
PHP
GoLang
SQL
R Language
Android Tutorial
Tutorials Archive

DSA
Data Structures
Algorithms
DSA for Beginners
Basic DSA Problems
DSA Roadmap
Top 100 DSA Interview Problems
DSA Roadmap by Sandeep Jain
All Cheat Sheets

Data Science & ML
Data Science With Python
Data Science For Beginner
Machine Learning
ML Maths
Data Visualisation
Pandas
NumPy
NLP
Deep Learning

Web Technologies
HTML
CSS
JavaScript
TypeScript
ReactJS
NextJS
Bootstrap
Web Design

Python Tutorial
Python Programming Examples
Python Projects
Python Tkinter
Python Web Scraping
OpenCV Tutorial
Python Interview Question
Django

Computer Science
Operating Systems
Computer Network
Database Management System
Software Engineering
Digital Logic Design
Engineering Maths
Software Development
Software Testing

DevOps
Git
Linux
AWS
Docker
Kubernetes
Azure
GCP
DevOps Roadmap

System Design
High Level Design
Low Level Design
UML Diagrams
Interview Guide
Design Patterns
OOAD
System Design Bootcamp
Interview Questions

Inteview Preparation
Competitive Programming
Top DS or Algo for CP
Company-Wise Recruitment Process
Company-Wise Preparation
Aptitude Preparation
Puzzles

School Subjects
Mathematics
Physics
Chemistry
Biology
Social Science
English Grammar
Commerce
World GK

GeeksforGeeks Videos
DSA
Python
Java
C++
Web Development
Data Science
CS Subjects

@GeeksforGeeks, Sanchhaya Education Private Limited, All rights reserved

We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy

Improvement

Suggest Changes

Help us improve. Share your suggestions to enhance the article. Contribute your expertise and make a difference in the GeeksforGeeks portal.

geeksforgeeks-suggest-icon

Create Improvement

Enhance the article with your expertise. Contribute to the GeeksforGeeks community and help create better learning resources for all.

geeksforgeeks-improvement-icon

Suggest Changes

min 4 words, max Words Limit:1000

Thank You!

Your suggestions are valuable to us.

What kind of Experience do you want to share?

Interview Experiences

Admission Experiences

Career Journeys

Work Experiences

Campus Experiences

Competitive Exam Experiences