Python Coding Challenge - Question with Answer (01251025)

 

Step-by-Step Execution

1. Initial list:
   nums = [1, 2, 3, 4]

2. Iteration 1:

   i = 1

   • Remove 1 → list becomes [2, 3, 4]

   • The iterator moves to next index (1) → which now points to 3.

3. Iteration 2:

   i = 3

   • Remove 3 → list becomes [2, 4]

   • The iterator moves to next index (2), but list length is now 2 → loop stops.

4. Loop ends.

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Final Output:

[2, 4]

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Key Takeaway:

Never modify (add/remove) a list while iterating directly over it —
it causes skipped elements or unexpected results.

✅ Better Way (Safe Approach):

nums = [1, 2, 3, 4]
for i in nums[:]: # use a copy of the list
    nums.remove(i)
print(nums) # Output: []

600 Days Python Coding Challenges with Explanation