[Solved] Identify the error in this code snippet that tries to update a transaction amount:transactions = [{'id': 't1', 'amount': 100}] transactions['t1']['amount'] = 150 | LLD

LLD - Design — Splitwise (Expense Sharing)

Identify the error in this code snippet that tries to update a transaction amount:

transactions = [{'id': 't1', 'amount': 100}]
transactions['t1']['amount'] = 150

Atransactions is a list, not a dictionary, so key access by 't1' is invalid

BThe amount key is misspelled

CThe assignment operator is incorrect

DThe list is empty

Step-by-Step Solution

Solution:

Step 1: Analyze data structure type
transactions is a list, so it cannot be accessed by string keys like 't1'.
Step 2: Understand correct access method
To update, you must find the dictionary in the list with id 't1' and then update its amount.
Final Answer:
transactions is a list, not a dictionary, so key access by 't1' is invalid -> Option A
Quick Check:
List accessed by key = Error [OK]

Quick Trick: Lists use index, dicts use keys for access [OK]

Common Mistakes:

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