What is the expected output of the following code? ``python def func(p1, p2): p1 = 1 p2[0] = 42 x = 3 y = [1, 2, 3] func(x, y) print(x, y[0]) ``

Question

def func(p1, p2):
 p1 = 1
 p2[0] = 42

x = 3
y = [1, 2, 3]

func(x, y)
print(x, y[0])

Options

• A142
• BThe code is erroneous.
• C11
• D31
• E342

• A
  3% (1)
• B
  6% (2)
• D
  11% (4)
• E
  80% (28)

Explanation

Option E (3 42) is correct because Python passes arguments by object reference: x is an integer (immutable), so reassigning p1 = 1 inside the function only rebinds the local variable - x remains 3. However, y is a list (mutable), and p2[0] = 42 mutates the original list object in place, so y[0] becomes 42.

• A (142) and C (11) are wrong because they imply x changed - it didn't; integers are immutable and reassigning a local parameter never affects the caller's variable.
• D (31) is wrong because it implies y[0] stayed as 1 - it was mutated to 42 through the list reference.
• B is wrong because the code is perfectly valid Python and runs without errors.

Memory tip: Think "rebind vs. mutate" - if a function reassigns a parameter (p1 = 1), the original is untouched; if it mutates the object (p2[0] = 42), the original changes. Immutables (int, str, tuple) can only be rebound; mutables (list, dict) can be changed in place.

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