Efficiently Search for Partial Dictionary Keys in Python

This guide explores how to merge two dictionaries in Python based on matching criteria. Learn a clear, step-by-step guide on creating a third dictionary that combines values from both source dictionaries based on partial key matching.
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Efficiently Merging Dictionaries with Partial Key Matching in Python

When working with dictionaries in Python, you might find yourself needing to merge two dictionaries based on specific criteria. For instance, you may want to create a new dictionary that combines values from two existing dictionaries when certain key patterns match.

In this guide, we will take a closer look at how to accomplish this task, especially when your dictionaries are structured in a specific way.

The Problem

Imagine you have two dictionaries:

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

Your goal is to create a third dictionary (d3) that merges values from d1 and d2 where the second part of the key in d1 matches the first part of the key in d2.

For example, you need to match 001-002 with 002-004 to create an entry like:

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

An Initial Attempt

Here's one way you might begin to approach this problem:

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

However, this approach has a time complexity of O(N*M), where N is the number of items in d1 and M is the number in d2. This can be slow with larger datasets.

A More Efficient Solution

To improve efficiency, we can reduce the time complexity to O(N + M). The strategy involves creating a lookup table for the first three characters of the keys in d2. Let’s break this down step-by-step:

Step 1: Create a Lookup Dictionary

Start by building a dictionary based on the keys of d2:

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

Step 2: Combine the Values

Next, you can use this lookup dictionary to efficiently merge the values:

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

Conclusion

Following these steps will yield a new dictionary d3 with combined values from d1 and d2 based on matching criteria, allowing you to efficiently handle larger sets of data without significant slowdowns.

In summary:

Create a lookup for the second dictionary's relevant parts.

Use this lookup to efficiently combine entries from both dictionaries into a new one.

Feel free to use this method in your projects to manage dictionary data effectively! Happy coding!