Python remove duplicates from list of dictionaries by key Removing duplicates from a list is an important data preprocessing step — for example, identifying the unique customers Mar 5, 2024 · The code uses dictionary comprehension to iterate over each unique key (obtained using set union), and for each key it calculates the sum of its values from all dictionaries in the list. For example, when you are collecting unique user IDs or distinct product names. 1. remove() list method only removes the first occurrence of an item. , API responses, JSON data, or database query results). This means that if we try to add a key that already exists in the dictionary, the new value Mar 14, 2017 · It looks like you want us to write some code for you. 7. Sep 12, 2022 · A Python list is an ordered, zero-indexed, and mutable collection of objects. However, this approach does not preserve the original order. Known for their efficiency and versatility, dictionaries are essential for tasks like data organization, quick lookups, and mapping relationships. We create it by placing objects of similar or different data types inside square brackets separated by commas. Jun 13, 2023 · In this example, we use a dictionary comprehension to create a new dictionary called unique_dict with the items from the input list as keys and None as the value for each key. May 31, 2017 · Yes, a dictionary has to have unique, hashable keys, so you'll need to look at non-keyed collections such as lists or tuples. In this article, we will explore several techniques to store multiple values for a single dictionary key. Learn how to create, modify, and use dictionaries in Python. This guide explains how to remove duplicate dictionaries from a list in Python, based on the uniqueness of a specific key (like an id). Whether you’re a beginner learning Sep 19, 2021 · Learn how to remove a Python dictionary key, using the pop method, the del keyword, and how to remove multiple Python dictionary keys. How can this done in the most efficient way? Sep 15, 2025 · Learn 4 easy methods to remove duplicates from a Python dictionary with examples. Nov 23, 2020 · You can remove duplicates from a Python using the dict. You'll learn how to create dictionaries, access their keys and values, update dictionaries, and more. One common task is to remove duplicate elements from these collections. For example, user Mar 17, 2020 · Removing Duplicates in Python Remove Duplicates in a List Duplicate removal is a common problem that often causes significant issues across industries. I only need to remove a dictionary if another dictionary already has the same key-value. Use Method 1 if order doesn’t matter and you want a concise solution. In Python 3. The methods from these links: Removing duplicates in lists How do you remove duplicates from a list in whilst Mar 8, 2023 · Python's dict class has a fromkeys class method which accepts an iterable and makes a new dictionary where the keys are the items from the given iterable. Python provides several built-in functions and custom solutions to achieve this efficiently. fromkeys (my_list)). Detect and eliminate duplicates in a list of dictionaries in Python - Using for Loop & set() function vs. Do you mean duplicate key, duplicate value, or duplicat key and value? Jun 13, 2022 · Removing duplicates from list of dicts is as simple as set (list) but i have got stuck with this specific task. An example of my list of dicts that works with this function is: [{'asndb_prefix': '164. Using Temporary List This is the brute-force Approach: Flatten the Dictionaries: Convert each dictionary into a list of tuples, where each tuple represents a key-value pair. Each key is associated with a single value, forming a key-value pair or item. Mar 31, 2023 · Given a dictionary, the task is to find keys with duplicate values. Step-by-step examples for clean. So I can turn all lists to tuples then use set and back to lists. Feb 26, 2024 · The code snippet defines a function remove_duplicates that iterates each key-value pair in the input dictionary and adds them to a result dictionary only if the value has not been seen before. 6 and above are ordered, so the keys are created in the same order as they appeared on the list. You can also convert a list to a set. Method 2: Using Dictionary Comprehension Python’s dictionary comprehension feature allows for a more Jul 24, 2025 · From simple key-value manipulations to complex transformations, these programs will help you master working with dictionaries and lists together in Python. (source) This is surprising to many readers because countless online resources Jan 24, 2025 · In Python programming, working with lists is a common task. Note that removing duplicate elements is equivalent to extracting only unique ele Nov 1, 2011 · In fact, despite the title "Python removing duplicates in lists", it doesn't seem like OP wanted to remove duplicates from within the same list at all. Dictionaries are written with curly brackets, and have keys and values: Jul 23, 2025 · We'll also look at how to remove spaces, unwanted characters, and duplicate dictionaries from lists. A frozenset is an immutable set, and since sets don't allow duplicates, it helps us remove repeated dictionaries efficiently. You can store the dicts using the value from "tmpl_id" as the key setting the dict as the value, if you get a dict with a higher 'qty_available' then you replace with the current dict : Dec 27, 2024 · Learn how to remove duplicates from an array (or list) in Python using methods like set(), list comprehensions, and pandas. Jul 11, 2025 · Removing duplicate dictionaries from a list can help us clean our data. Proposed A… May 8, 2023 · This article describes how to generate a new list in Python by removing and extracting duplicate elements from a list. Track Duplicates: Use a dictionary to keep track of how many times each key-value pair appears. In this case, what I would expect to get is: Jun 16, 2022 · dedupe_dict = {str(item): item for item in time_array_final} Upon encountering a duplicate item, the dict comprehension will overwrite the previous item with the duplicate one, but that doesn't make any material difference because both items are identical. Mastering these collections is not just essential for writing efficient code Use additional methods- list comprehension and Array. Example: Apr 16, 2025 · In Python programming, dealing with data often involves handling collections such as lists, sets, and dictionaries. Understanding Dictionary Key Constraints In Python, dictionary keys must be unique. See the related question How to merge dicts, collecting values from matching keys? for dealing with this problem. They allow you to store an ordered collection of items. May 5, 2020 · Method 2: Temporary Dictionary Conversion Algorithm: A more efficient way in terms of time complexity is to create a dictionary out of the elements in the list to remove all duplicates and convert the dictionary back to a list. Jan 10, 2014 · I have a list of dictionaries sorted by a specific key. Mar 10, 2024 · To find keys with duplicate values in a dictionary, one approach is to invert the dictionary, mapping each value to a list of keys that have that value. , `score`, `rating`). The syntax looks as follows: Sep 21, 2019 · One option is to create an intermediate dict (not a list of dicts) similar to your second approach. Method 3: Using collections. Great. This tutorial covers all dictionary operations with practical examples for beginners and advanced users. Each dictionary contains 32 elements, and there over 4000 dictionaries in the list. Dictionary Dictionaries are used to store data values in key:value pairs. Converting the list to a set removes all duplicates since sets only store unique elements. The second is that you don't explain exactly what counts as a duplicate. The simplest way to remove duplicates is by converting a list to a set. For that purpose you need to categorize based on dict items. You must convert the dictionary or set back into a list to see a list whose duplicates have been removed. Aug 14, 2009 · What happens if the value for one key matches the value for another key in another dict? Also, by the way, name your lists something other than list, or you'll overwrite the actual list in the built-in namespace, and you can't call the list() function later on. And I want to remove duplicate elements from it. Oct 13, 2022 · cs+=1 mglist. All of the dictionaries are unique, but there is a specific key I would like to deduplicate on, keeping the dict Jan 6, 2012 · My goal is to remove all records where the dst, src, and alias have all been duplicated - regardless of the key. Avoid Method 3 unless you’re certain tuples contain unique elements and order Dec 5, 2024 · Removing duplicates from a list is a common operation in Python which is useful in scenarios where unique elements are required. Jun 20, 2025 · A reminder that the . In some cases, this can be harmful to your software. Defining a Dictionary # In Python, a dictionary, shortened as dict, is a data type that stores collections of mappings between keys and values. Choose the method that best suits Jan 25, 2024 · Learn Python Tutorial for beginners and professional with various python topics such as loops, strings, lists, dictionary, tuples, date, time, files, functions Dec 16, 2024 · In this tutorial, you'll learn how to work with Python dictionaries to help you process data more efficiently. This will automatically remove any duplicates because dictionaries cannot have duplicate keys. We’ll explore different methods to merge dictionaries in a list. For a refresher on how a Python List works, kindly refer to this DataQuest tutorial. Each status code has duplicates for the keys of the dictionary. In this instance, you may need to remove the duplicates from your dictionary. Nov 4, 2023 · Discover expert techniques to identify and handle duplicate values in Python dictionaries. Only of tuples. May 19, 2023 · Conclusion Removing duplicates from a list is an essential operation in programming. Example: Apr 21, 2024 · Learn how to remove duplicates in JSON arrays with Python: Learn techniques for exact, key-based, and deep nested duplicates in this tutorial. Jul 23, 2025 · In Python, dictionaries are used to store key-value pairs. Aug 10, 2018 · Below is the code that I have so far, this gets me as far as having two dictionaries but 1) I think this is horribly inefficent and 2) I can't work out how to remove the first instance of a duplicate dictionary. Introduction Removing duplicates from lists is a common task in Python programming that can significantly improve code efficiency and data management. May 30, 2024 · We know that dictionary won’t allow duplicate keys. But I won't dwell on these versions any longer. Use dupKeys = [] if your source data is comprised of EXACT formatted dictionaries and looking for duplicates. A frozenset() is the 4 days ago · In the world of data processing, lists of dictionaries are a common data structure—often used to represent collections of records (e. Dec 21, 2021 · The second dictionary is also unique. defaultdict class can handle default values for missing keys, making it Oct 17, 2021 · Learn how to use Python to remove duplicates from a list, including how to maintain order from the original list, using seven methods. Common solutions like list (dict. list & set comprehension vs. fromkeys (lst)) or using sets are either non-intuitive or don’t preserve order. When working with Python dictionaries, we […] Jan 26, 2025 · In Python programming, lists are a fundamental data structure used to store a collection of elements. Was if it a normal list not of lists I could used set. Why remove duplicates from the list? Removing duplicates from a list is crucial in maintaining data accuracy, optimizing code performance, and promoting efficient data handling and analysis. The methods from these links: Removing duplicates in lists How do you remove duplicates from a list in whilst Jun 20, 2025 · A reminder that the . Sets, as you're probably aware, will also remove duplicates. A common task when working with lists is removing duplicates. [1, 2, 3, 4] and [1, 3, 4], and remove from the first those which are present in the second, to get [2]. com Mar 4, 2025 · Learn how to remove duplicates from a list in Python using `set ()`, list comprehension, and `dict. Using a temporary List and Looping Using set () built-in method Using Dictionary Keys List count () function List Comprehension Removing Duplicates from a List Python list can contain duplicate elements. 39. fromkeys (), which generates a dictionary that removes any duplicate values. In general if you want to find duplicates in a list of dictionaries you should categorize your dictionaries in a way that duplicate ones stay in same groups. This article has demonstrated how to use set(), dict. In this blog, we’ll focus on a Jul 12, 2025 · Dictionaries often contain lists or sets as their values and sometimes we want to remove duplicate values across all dictionary keys. has_key('key'): del d['key'] However, I need to remove multiple entries from a dictionary safely. Proposed A… Nov 1, 2011 · In fact, despite the title "Python removing duplicates in lists", it doesn't seem like OP wanted to remove duplicates from within the same list at all. Lists are versatile data structures that can hold various types of elements. fromkeys ()`. Jan 23, 2012 · Please define "duplicate". fromkeys ()) Since dictionary keys are unique, we can use dict. A unique () method is available in numpy and pandas modules which will return only unique values by removing duplicates. Nov 14, 2025 · This blog post will guide you through **four practical methods** to remove duplicates from a list of dictionaries based on the `'doc'` key. Loop through all entries in list_of_unique_dicts, if the key for this entry doesn't exist in the intermediate dict, add it, otherwise update the value in the intermediate dict. This method effectively removes duplicate values while maintaining the order of initial insertion. However, dictionaries do not support duplicate keys. It doesn't remove all of them. I was thinking of defining the entries in a tuple as I will need to do this more than once. We'll explore using dictionary comprehensions (most efficient), for loops, enumerate, and, briefly, Pandas (for more complex scenarios). , a key in a dictionary or Mar 27, 2012 · The first thing to be aware of is that you don't have two different dictionaries. However, often we encounter situations where we need to remove duplicate elements from a list. For instance, consider a list of dictionaries where each dictionary represents a unique data record. This gives us a merged dictionary with summed values for the duplicate keys. Removing these duplicates can be crucial for various tasks, such as data cleaning, ensuring uniqueness in sets of values, or optimizing algorithms. Sometimes people want to "combine" or "merge" multiple existing dictionaries by just putting all the items into a single dict, and are surprised or annoyed that duplicate keys are overwritten. , `user_id`, `email`) while retaining the entry with the highest associated value (e. Nov 23, 2024 · Merging Multiple Python Dictionaries with Duplicate Keys: Essential Techniques for Developers Merging multiple dictionaries in Python, especially when encountering duplicate keys, is a common challenge for developers. From simple key-value removal to complex filtering operations, these programs will help you master dictionary manipulation in Python. Nov 11, 2020 · I'm trying to filter out my list of dictionaries by two keys. Ever wondered whether to use a list Mar 4, 2025 · Learn how to remove duplicates from a list in Python using `set ()`, list comprehension, and `dict. Using set () method is most efficient for unordered lists. Try this and post the results. It preserves order, handles tuples with duplicate elements, and is efficient for most use cases. Apr 27, 2023 · Sometimes, while working with Python dictionaries, we can have problem in which we need to perform the removal of all the duplicate values of dictionary, and we are not concerned if any key get removed in the process. 3 days ago · Python: How to Remove Duplicates by Key in a List of Dictionaries, Keep Highest Score, and Sort Results In data processing, it’s common to encounter lists of dictionaries—for example, data fetched from APIs, CSV exports, or user records. Merging dictionaries involves combining multiple dictionaries into a single dictionary combining common key values. I have a dictionary of HTTP codes to status text (404: Not Found, for example). In the example when making the comparison I want to ignore keys STATUS and Ferry LAST SPEED. 2 that I am attempting to "deduplicate". 18 hours ago · In data processing, lists are a fundamental structure for storing collections of items. Nov 6, 2024 · A detailed guide on various methods to efficiently remove duplicates from a list of lists in Python, including practical examples and performance considerations. Create a dictionary, using the List items as keys. However, sometimes lists can contain duplicate elements, which might not be desirable in certain scenarios. The third is that you don't say what to do with the relevance key. But this isn't fast. This blog post will explore different ways to remove duplicates from a Jun 28, 2025 · Python List Exercises, Practice and Solution: Write a Python program to remove duplicate dictionary entries from a given list. While many users are willing to produce code for a coder in distress, they usually only help when the poster has already tried to solve the problem on their own. Nov 27, 2015 · 39 You can easily remove duplicate keys by dictionary comprehension, since dictionary does not allow duplicate keys, as below- Jul 23, 2025 · Using Dictionary Keys (dict. This means that if we try to add a key that already exists in the dictionary, the new value I would like Python to go through list A, see if any duplicates exist, and not only remove the duplicates in A, but also remove the element in B that matches that duplicate element, respectively. Aug 26, 2016 · The outer dictionary has only 1 element that contains a list, with 1 element (in this example) that contains the list of dictionaries with the actual data (the mentioned dictionary with one key that contains a dictionary with the properties). Method #1: Using Naive approach In this method first, we convert dictionary values to keys with the inverse mapping and then find the duplicate keys Feb 17, 2023 · In this article, we will be discussing how to remove duplicate elements from a dictionary in Python. Feb 17, 2023 · In this article, we will be discussing how to remove duplicate elements from a dictionary in Python. , "Apple" and "apple")—can skew analysis, clutter outputs, or break downstream logic. To remove duplicates we invoke the dict. ] The actual dictionary has many other keys, but what I'm trying to do is to delete all the entries that have the exact same key pair values, except for the date. I did it like this i want some better solution using remove duplicates I have a list of dictionaries in Python 3. Using set () We can use set () to remove duplicates from the list. However, it's common to encounter lists that contain duplicate elements. A frequent challenge is **deduplicating entries by a specific key** (e. Feb 24, 2012 · A lot of good examples searching for duplicate values and keys, below is the way we filter out whole dictionary duplicate data in lists. Mar 23, 2019 · – Aran-Fey Mar 23, 2019 at 18:56 Possible duplicate of Remove duplicate dict in list in Python – Pedro Rodrigues Mar 23, 2019 at 18:58 Nov 13, 2025 · Python’s built-in data structures—**lists**, **dictionaries**, and **sets**—are workhorses for storing and manipulating data. Removing such duplicates is a common task, but it becomes tricky when **preserving the original order of elements** is critical. Various Methods to Remove Duplicate Dictionaries List Comprehension Jun 7, 2022 · Dictionary keys have to be unique; this is a property we make use of to remove duplicate values from a list. While they all hold collections of items, their design differs drastically, making each better suited for specific tasks. Boost your Python programming with proven methods for every use case. Let’s look into examples of removing the duplicate elements in different ways. Jul 23, 2025 · Explanation : gfg while merging retains value of 1, and "best" is added to dictionary as key from other list's 1st dictionary ( same index ). That is, to delete all duplicates (which are not really exact duplicates as only the date varies). Apr 14, 2023 · Given a list of dictionaries, remove all the dictionaries which are duplicate with respect to K key. index () method, del keyword, for-loop, and dict methods. fromkeys(), list comprehension with an if condition, and a for loop with an if condition to remove duplicates from lists in Python. Jul 16, 2024 · To remove duplicates from a Python list while preserving order, create a dictionary from the list and then extract its keys as a new list: list (dict. How does this rookie accomplish this? Also, my limited understanding of Python interprets the data structure as a dictionary with the values stored in dictionaries a dict of dicts, is this correct? I presently have the ability to remove duplicates if there is no key in front of the nested dictionary. 3 days ago · In data processing, it’s common to encounter lists of dictionaries—for example, data fetched from APIs, CSV exports, or user records. append(mg[i]) print(cr) print(cs) I want to delete duplicate rows and then count frequency of id (in first and second column) in this list of dictionary how I could solve my problem with iteration and remove duplication how to delete duplicate dictionaries in list of dictionaries and extract the values of dictionary? Aug 8, 2018 · I want to remove duplicate dictionaries and if more than one dictionaries have same key but different values then choose that dictionary with higher value. If you’ve ever needed to combine, extract, or transform data stored in both structures, this guide has everything you need. We’ll cover everything from basic loops to advanced tools like Pandas, explaining pros, cons, and use cases for each approach. I have a huge list of items and I need to find a way to filter out those items that have repeated 'id' and 'updated_at' keys. Jun 22, 2020 · I would like to find duplicates in a list of dict ignoring specific keys and removing both the duplicate and original list. To clean up such overlaps, we can use various methods to ensure that each value is unique Mar 27, 2012 · The first thing to be aware of is that you don't have two different dictionaries. defaultdict The collections. 1 day ago · Performing list(d) on a dictionary returns a list of all the keys used in the dictionary, in insertion order (if you want it sorted, just use sorted(d) instead). Dec 2, 2024 · Rationale: Currently there’s no straightforward way to remove duplicates while preserving order. Then at the end, you can convert this intermediate dict into a list of dicts. Python provides multiple built-in methods and techniques to efficiently handle duplicate values while maintaining list order and data integrity. May 8, 2023 · This article describes how to generate a new list in Python by removing and extracting duplicate elements from a list. Merge List of Dictionaries in Python (2 Examples) In this tutorial, you’ll learn how to merge a list of dictionaries in Python. For example, consider the dictionary d = {'a': [1, 2, 3], 'b': [3, 4, 5], 'c': [5, 6]}. A dictionary is a collection which is ordered*, changeable and do not allow duplicates. Understanding how to delete Jul 23, 2025 · In Python, dictionaries are used to store key-value pairs. A good way to demonstrate this effort is to include the code you've written so far (forming a minimal reproducible example), example input (if there is any), the expected output Jun 17, 2025 · In Python, lists are one of the most commonly used data structures. Aug 4, 2010 · I want to remove duplicate values just keep one K/V pair, Regarding the "key" selection of those duplicated values, it may be max or min or by random select one of those duplicated item's key. Oct 24, 2023 · how to remove multiple key from this list of dictionary. But compare the output from the two versions. I'll assume that two dictionaries with equivalent type and name keys are identical, and that you want the relevance values to be 18 hours ago · In Python, lists are versatile data structures used to store collections of items. As of Python version 3. Aug 3, 2022 · There are many ways to remove duplicates from a Python List. This preserves the order of the original list elements. lst or list_ are fairly common alternatives. For example, if a company’s marketing team … Oct 22, 2020 · Dictionaries in Python 3. The number 3 appears under both 'a' and 'b', and 5 appears under both 'b' and 'c'. In this blog post, we will explore different ways to remove duplicates from a list Oct 22, 2020 · Dictionaries in Python 3. 5. Feb 22, 2024 · Problem Formulation: You’re working with a list of dictionaries in Python, and you need a way to remove duplicates based on a specific key while preserving the original order. This blog post will explore different methods to achieve this, from basic approaches to more advanced and efficient techniques. Is there a way to remove duplicate entries from the dictionary based on the key reoccurring without using a for loop? I'd also like to keep to base Python if possible (EG no Pandas DataFrame). Apr 20, 2020 · Related blog articles: Python Remove Duplicates From List of Lists Python List Remove The Ultimate Guide to Python Dictionaries! Do Python Dictionaries Preserve the Ordering of the Keys? Surprisingly, the dictionary keys in Python preserve the order of the elements. I need code to work through the list and return a new list with all duplicates removed. The goal is to create a consolidated dictionary that efficiently includes all values under their respective keys, such that if a key appears in more than one dictionary, its Jan 15, 2015 · I want to delete all the duplicate values und in 'key_file' and their other values in the other keys ('key1' and 'key2'). Duplicated items from a list are ignored (since dictionaries can't have duplicated keys). The difference between these output lists gives a clue to what's coming next. Note that removing duplicate elements is equivalent to extracting only unique ele Nov 6, 2024 · A comprehensive guide on various methods to remove duplicates from a list of lists in Python with code examples and performance benchmarking. Now, since for dictionaries Order is not an important factor you need to use a container that is both hashable and doesn't keep the order of its container. Aug 1, 2023 · The below article will provide information on different methods to remove duplicate dictionaries in a list. However, duplicates—especially those differing only in case (e. See How can I properly hash dictionaries with a common set of keys, for deduplication purposes? for in-depth, technical discussion of why the usual approach for deduplicating a list (explained at Removing duplicates in lists) does not work. Removing duplicates can be crucial for data cleaning, ensuring data integrity, and optimizing algorithms that rely on unique data. But unfortunate that list is not hashable and can't make set of lists. fromkeys () to remove duplicates while preserving the order of elements. Choosing the right one can drastically impact your code’s readability, performance, and maintainability. 3 days ago · Conclusion To get unique tuples in a Python list (irrespective of element order), the dictionary method (Method 2) is generally the best choice. 1. A dictionary is a data structure that stores key-value pairs, and it is an essential data type to understand when learning Python. 7, dictionaries are ordered. 6 and earlier, dictionaries are unordered. Both algorithms remove duplicates. pandas May 21, 2018 · I have a list of dictionaries in Python 3. These include: for loop, set () function, list comprehension, dictionary, etc. See full list on bobbyhadz. so if we consider the list elements as keys, we can get rid of duplicates. The option of directly selecting the duplicate dictionaries is not available and thus we will have to use different methods and features of python to remove the dictionaries. In this article, we will explore various methods to Remove duplicate dicts in the list. This guide includes step-by-step examples. A dictionary uses curly brackets {} and defines each entry with a key:value pair, separated by commas. The term duplicates mean the elements which are repeated. Let's discuss a few methods for the same. How can we find and remove duplicate values along with their keys from a dictionary. I need to filter a list of dicts only by some keys and keep only the first elements fl 1 day ago · Performing list(d) on a dictionary returns a list of all the keys used in the dictionary, in insertion order (if you want it sorted, just use sorted(d) instead). However, not all duplicates are created equal: **consecutive duplicates** (items that repeat one after another) often require special handling, especially when duplicates are defined by a specific attribute of the items (e. May 30, 2024 · How to remove multiple keys from Python Dictionary? To remove multiple keys you have to create a list or set with the keys you want to delete from a dictionary and iterate it and use either the del keyword or the pop() function to delete each key from the list. So, yes, the order of the elements is preserved. After deduplication, you may also need to **sort the results** for Feb 22, 2024 · Problem Formulation: When working with lists of dictionaries in Python, one common task is to remove duplicates – dictionaries with identical key-value pairs. Python provides multiple methods to achieve this. Explore ways to remove duplicates from Python lists useful when cleaning data, optimizing performance, or ensuring uniqueness. This kind of application can occur in school programming and day-day programming. Approach : Using loop + keys () In this we reconstruct the key value pair in accordance of all the keys not recurring, checking using in operator and extracting keys using keys (). Clean your data like a pro using sets, loops, dict comprehension, and pandas. g. This tutorial explores various techniques to eliminate duplicate elements from Python lists, providing developers with practical strategies to clean and optimize their data structures. Jan 25, 2012 · if d. fromkeys() function which creates a new dictionary from a list of keys. Rather, it looks like OP wanted to take two lists e. Duplicates may arise due to data entry errors or during data processing. This can be efficiently achieved by using a defaultdict from the collections module, which allows us to append keys to each value’s list without needing to check if the key already exists. append(mg[i]) print(cr) print(cs) I want to delete duplicate rows and then count frequency of id (in first and second column) in this list of dictionary how I could solve my problem with iteration and remove duplication how to delete duplicate dictionaries in list of dictionaries and extract the values of dictionary? Aug 8, 2018 · 3 This question already has answers here: Remove duplicate dict in list in Python (19 answers) Removing duplicate elements from Python lists is a common data cleaning task that developers encounter regularly. Sep 21, 2025 · Python’s collections module — lists, dictionaries, sets, and tuples — form the backbone of Python programming. You have two different lists of dictionaries. Identify Duplicates: Extract key-value pairs that appear more than once in the list of dictionaries. When working with Python dictionaries, you may encounter circumstances where there are duplicate values in the dictionary. Do you mean duplicate key, duplicate value, or duplicat key and value? Mastering Python Dictionaries: A Comprehensive Guide to Key-Value Collections Python’s dictionary is a cornerstone data structure, offering a powerful and flexible way to store and manipulate key-value pairs. , a key in a dictionary or Jan 7, 2017 · Given n dictionaries, write a function that will return a unique dictionary with a list of values for duplicate keys. . A frequent challenge when working with such data is **deduplication**: identifying and removing duplicate entries while retaining specific records based on a criteria. All of the dictionaries are unique, but there is a specific key I would like to deduplicate on, keeping the dictionary with the mo