Скачать или смотреть How to Remove Duplicate Values in Multiple Dictionary Lists in Python

Learn how to effectively remove duplicate entries from multiple lists of dictionaries in Python by filtering based on specific keys, ensuring unique values remain.
---
This video is based on the question https://stackoverflow.com/q/70624165/ asked by the user 'wenz' ( https://stackoverflow.com/u/17829888/ ) and on the answer https://stackoverflow.com/a/70625189/ provided by the user 'Alain T.' ( https://stackoverflow.com/u/5237560/ ) 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: remove duplicate value based on comparison in multiple dictionary list python

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.
---
Introduction: Filtering Dictionaries in Python

In the world of programming, particularly with Python, we often encounter scenarios where we need to manipulate lists of data. One common problem is how to remove duplicate values based on certain criteria. For instance, consider two lists of dictionaries where we want to filter elements from one list based on the presence of their keys in another list.

The Problem

Imagine we have two lists, a and b, constructed as follows:

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

Your goal is to filter out entries from the list b based solely on the "name" values present in list a. Furthermore, you want to ensure that the results contain unique names only, even when they appear multiple times in list b.

However, your initial attempt:

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

results in you getting only the entries from b that match those in a, which is the opposite of what you expect to achieve. Instead, you were looking for:

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

In this guide, we will dive into a solution that accomplishes this task seamlessly.

Solution: Using a Temporary Dictionary to Filter Data

To achieve the desired results, we can use a strategic approach involving dictionaries. Here's how to do it:

Step 1: Create a Set of Names from List a

First, we need to extract and store names from list a into a set. This allows us to quickly check for duplicates during the filtering process.

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

Step 2: Build a Temporary Dictionary

Next, we will iterate through the list b and construct a temporary dictionary. This dictionary will use name as the key and store the corresponding dictionary as the value, but only if the name is not found in a. By doing this, we ensure that only unique entries from b are retained.

Here's the code snippet for this step:

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

Step 3: Convert the Temporary Dictionary Back to a List

Finally, we will extract the values from the temporary dictionary and convert them into a list, which will give us the desired unique entries from list b:

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

Final Output

When you print newb:

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

You will receive the output:

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

Conclusion

The approach described above allows you to effectively remove duplicates based on specific criteria from multiple lists of dictionaries in Python. By leveraging the capabilities of sets and dictionaries, you can filter data efficiently while ensuring that you maintain the integrity of unique entries.

Key Takeaway

By creating a temporary dictionary and filtering out names based on their presence in another list, we streamline the filtering process and achieve clear, effective results. Keep practicing and exploring the power that Python offers for data manipulation!