What is the output of the following Python code?x = [1, 2, 3] y = x y += [4] z = x + [5] print(x, z)

x = [1, 2, 3]
y = x
y += [4]
z = x + [5]
print(x, z)

Explanation

y += [4] extends the shared list in place so x becomes [1, 2, 3, 4]; x + [5] then creates a new list.