Question 20 (Beginner):
What is the output of this Python code?

x = [1, 2, 3]
y = x
y.append(4)
print(x)

A) [1, 2, 3]
B) [1, 2, 3, 4]
C) [4, 3, 2, 1]
D) Raises an error

#Python #Lists #Variables #Beginner

✅ By: https://t.iss.one/DataScienceQ

✅ **Correct answer: B) `[1, 2, 3, 4]`**

*Explanation:
- `y = x` creates a reference to the same list object
- Modifying `y` affects `x` because they point to the same memory location
- To create an independent copy, use y = x.copy() or y = list(x)*