pythonintermediate10 minutes

Fix the Off-By-One Error in List Processing Function

Identify and fix the bug in a Python function designed to process a list of numbers and return a transformed list. The current implementation has an off-by-one error causing incorrect output.

Challenge prompt

The function `transform_numbers` is intended to return a new list where each element is the sum of the current element and the next element in the original list. However, the implementation has a bug causing it to skip the last element or produce an incorrect result. Your task is to fix the bug while keeping the intended logic intact. Example: For input [1, 2, 3, 4], the expected output is [3, 5, 7] because: - 1 + 2 = 3 - 2 + 3 = 5 - 3 + 4 = 7 Fix the code provided so that it works correctly for any list of integers with length >= 2.

Guidance

• Check the loop boundaries and index usage carefully to identify where the off-by-one error occurs.
• Make sure you do not access indexes out of range when summing elements.

Hints

• Remember that list indexes in Python start at 0 and go up to len(list)-1.
• Try printing indexes inside the loop to understand which elements are being accessed.

Starter code

def transform_numbers(nums):
    result = []
    for i in range(len(nums)):
        result.append(nums[i] + nums[i+1])
    return result

Expected output

[3, 5, 7]

Core concepts

list indexingloopsoff-by-one errordebugging

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