Скачать или смотреть How to Compare Two Lists of Dictionaries in Python

Learn how to efficiently `compare` two lists of dictionaries in Python, identifying updates and new entries using clear coding examples!
---
This video is based on the question https://stackoverflow.com/q/63260423/ asked by the user 'John' ( https://stackoverflow.com/u/11839859/ ) and on the answer https://stackoverflow.com/a/63260516/ provided by the user 'Andrej Kesely' ( https://stackoverflow.com/u/10035985/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to compare 2 lists of dictionnaries?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Compare Two Lists of Dictionaries in Python

Comparing two lists of dictionaries can be a common task when working with data in Python. You may find yourself needing to check if items from one list exist in another and whether their properties match. In this post, we'll explore how to solve this problem step-by-step using Python, providing a clear approach to achieve the desired results.

The Problem

Imagine you are working with two lists containing dictionaries, where each dictionary represents an item with a unique code and a description. Here's a quick look at our example data:

[[See Video to Reveal this Text or Code Snippet]]

Goals

You want to achieve the following:

Updates: If an entry from list2 shares a code with an entry in list1, but the description differs, you should record it in a new list called updates.

New entries: If an entry from list2 does not exist in list1, it should be added to a new list called new.

The expected outputs for these lists after processing should look like this:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

To efficiently compare the two lists, we can convert list1 into a dictionary. This makes it quick to access descriptions by code, allowing for fast comparisons. Here are the steps to implement this solution:

Step 1: Convert list1 to a Dictionary

Convert list1 into a dictionary where the codes are the keys, and the descriptions are the values. This change will help streamline our comparisons.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Initialize the Lists for Updates and New Entries

Before looping through list2, we need to prepare two empty lists to collect our results.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Compare Items from list2 with list1

Using a loop, we can now check each dictionary in list2:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Print the Results

Finally, we can print out our updates and new lists to see the result:

[[See Video to Reveal this Text or Code Snippet]]

Complete Code Example

Here is the complete code snippet for your reference:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By adapting the above technique of transforming the lists into a dictionary, you can quickly compare and analyze the items. This method is efficient and straightforward, making it easy to identify updates and new entries. Now you are well-equipped to handle similar comparisons in your own Python projects!