What will be the output of executing the following Python list operations?
a = [1, 2, 3]
b = a
b.append(4)
print(len(a))
Answer and explanation
Correct answer: C. 4
- Step 1: In Python, variable assignment `b = a` assigns an object reference, not a deep or shallow copy.
- Step 2: Both `a` and `b` reference the identical underlying list in memory. Appending 4 via `b` modifies the list to `[1, 2, 3, 4]`, making `len(a)` equal to 4.
Answer
4.
Why not the others: 3 assumes `a` remains unmodified; 1 and Error misunderstand Python object reference semantics.
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