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Unexpected KeyError When Accessing Nested Dictionary Elements in Python

👀 Views: 3 đŸ’Ŧ Answers: 1 📅 Created: 2025-06-05
python dictionary keyerror Python

I'm following best practices but I'm stuck on something that should probably be simple... I've spent hours debugging this and I'm working on a project and hit a roadblock. I'm working with a `KeyError` when trying to access elements from a nested dictionary. I've structured my data to represent a user profile as follows: ```python user_profiles = { 'user1': {'name': 'Alice', 'age': 30, 'preferences': {'color': 'blue', 'food': 'pizza'}}, 'user2': {'name': 'Bob', 'age': 25, 'preferences': {'color': 'green', 'food': 'sushi'}} } ``` I want to retrieve the favorite food of a specific user, say `user1`. My code looks like this: ```python user_id = 'user1' try: favorite_food = user_profiles[user_id]['preferences']['food'] print(f"{user_id}'s favorite food is {favorite_food}") except KeyError as e: print(f"KeyError: {e} for user {user_id}") ``` However, I occasionally receive a `KeyError: 'food' for user user1'`, even though I can see that the structure is correct. I confirmed that accessing `'preferences'` works as expected. I even printed the entire `user_profiles[user_id]['preferences']` just before the failing line, and it returns `{'color': 'blue', 'food': 'pizza'}`. I've also checked if `user_id` has any leading or trailing whitespace, but that seems fine. Could this be a case of concurrent modification of the `user_profiles` dictionary, or am I overlooking something else? I'd appreciate any insights into why this might be happening. My Python version is 3.9.7, and I am running the code in a local script. For context: I'm using Python on macOS. Thanks for any help you can provide! Thanks for your help in advance! I'm working on a web app that needs to handle this. Any pointers in the right direction?