👀 Views: 37 💬 Answers: 1 📅 Created: 2025-06-13

python dictionary nested-dictionary Python

I've been banging my head against this for hours... I'm currently working on a Python project where I'm using nested dictionaries to store user preferences. However, I'm running into issues when trying to update nested values without losing existing data. For example, I have the following dictionary structure: ```python user_preferences = { 'user1': {'theme': 'dark', 'notifications': True}, 'user2': {'theme': 'light', 'notifications': False} } ``` When I try to update a specific user's theme, I'm overwriting the entire dictionary instead of just updating the specific key. Here's the code I'm using: ```python def update_theme(user_id, new_theme): user_preferences[user_id] = {'theme': new_theme} ``` Calling `update_theme('user1', 'blue')` results in: ```python {'user1': {'theme': 'blue'}, 'user2': {'theme': 'light', 'notifications': False}} ``` As you can see, I lose the `notifications` setting for `user1`. What I want is to merge the new theme with the existing preferences so that the update looks like this: ```python {'user1': {'theme': 'blue', 'notifications': True}, 'user2': {'theme': 'light', 'notifications': False}} ``` I've tried using the `update()` method but it doesn't seem to work as expected. Is there a better way to achieve this without losing the existing data? I'm using Python 3.9 and would appreciate any suggestions or best practices for managing nested dictionaries effectively. I'm working on a application that needs to handle this.