Python Coding Challenge - Question with Answer (ID -090526)

 

Explanation:

🔹 Step 1: Create Tuple

x = ([],)

x is a tuple

Tuple is immutable ❗

Inside tuple:

[]

is a mutable list

👉 Current value:

([],)

🔹 Step 2: Execute x[0] += [1]

x[0] += [1]

This line is tricky 😈

Python internally performs TWO actions.

⚡ Step 2.1: Modify the List

[] += [1]

This updates list in-place.

👉 List becomes:

[1]

So internally:

x → ([1],)

⚡ Step 2.2: Try Reassignment

After modifying list, Python also tries:

x[0] = [1]

⚠️ But tuple is immutable ❌

Tuple does NOT allow item assignment.

🔹 Step 3: Error Occurs

Python raises:

TypeError

👉 Program stops here

🔹 Step 4: print(x) Never Executes

print(x)

This line is never reached because error already happened.

⚡ Important Twist 😈

Even though error occurs:

👉 list WAS modified before error

Internally tuple becomes:

([1],)

But print never runs.

🔥 Final Output

TypeError