Скачать или смотреть Change Key in Python Dictionary: A Simple Solution

Discover how to effectively change keys in a Python dictionary without encountering errors. Follow step-by-step instructions and examples to master this essential programming skill.
---
This video is based on the question https://stackoverflow.com/q/73219226/ asked by the user 'bestmovie clips' ( https://stackoverflow.com/u/19311212/ ) and on the answer https://stackoverflow.com/a/73219349/ provided by the user 'ArrowRise' ( https://stackoverflow.com/u/14868949/ ) 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 change key in python dictionary

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.
---
Change Key in Python Dictionary: A Simple Solution

When working with Python dictionaries, you might find yourself needing to change an existing key. This process can seem daunting, particularly when you're not sure how to execute it correctly without running into errors. In this guide, we'll take a closer look at how to change a key in a Python dictionary, using a specific example to illustrate the process.

The Problem: Modifying Dictionary Keys

Consider the following dictionary:

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

You might want to change the key '998905653388.0' to '998905653388' so that there are no duplicate keys. To achieve this, you might try to iterate through the keys, split them, and update the values accordingly. However, doing so directly can lead to errors, specifically a TypeError: unhashable type: 'list', which indicates that the key cannot be modified in that manner.

The Solution: Correctly Changing Keys

To effectively change keys in a Python dictionary without causing errors, here’s a step-by-step solution:

Iterate Through a Copy of the Keys:
When changing keys, it’s essential to avoid modifying the dictionary while you’re iterating over it. Therefore, create a list of the keys to iterate through.

Create New Key-Value Pairs:
For each key, construct a new key that you would like to use, and assign the corresponding values to it.

Remove Old Keys:
Use the pop() method to remove the old key from the dictionary after reassigning its value to the new key.

Here's the code that demonstrates this process:

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

Breakdown of the Code

list(data.keys()): This creates a copy of the keys that we can safely iterate through.

key.split('.')[0]: This expression splits the key string on the dot and retrieves the original part of the key.

data[key.split('.')[0]] = data.pop(key): This line assigns the values associated with the old key to the new key and removes the old key from the dictionary in one go.

Conclusion

Changing keys in a Python dictionary doesn’t have to be complicated. By creating a list of keys and carefully managing how you modify the dictionary, you can avoid common pitfalls and errors. Remember to always keep the integrity of your data in mind when making such changes.

Follow these steps, and you'll serve yourself well in your Python programming journey. Happy coding!