Tricky Questions

What is the output of the following Python code?

a = [1, 2, 3]
b = a[:]
a[0] = 10
print(b)

A:

[1, 2, 3]

B:

[10, 2, 3]

C:

This code will result in an error.

D:

[10, 2, 3] (but with a warning)

Answer: A

Slicing creates a new copy of the list, so modifying a does not affect b.

📖

Consider the following Python code:

class CustomClass:
    def __init__(self, value):
        self.value = value

    def __eq__(self, other):
        return self.value == other.value

obj1 = CustomClass(10)
obj2 = CustomClass(10)
result = obj1 == obj2
print(result)

What will be the value of result?

A:

True

B:

False

C:

This code will result in an error.

D:

This code will result in an infinite loop.

Answer: A

The custom __eq__ method is defined to compare the value attribute of the objects.

📖

What is the output of the following Python code?

result = 1.0 - 0.1 - 0.1 - 0.1 - 0.1 - 0.1
print(result)

A:

0.5000000000000001

B:

0.6

C:

0.4

D:

0.0

Answer: A

Floating-point arithmetic may result in small precision errors, and the actual result is approximately 0.5.

📖

What will be the output of the following Python code?

def outer_func(x):
    def inner_func():
        return x + 1
    return inner_func

closure1 = outer_func(5)
closure2 = outer_func(10)

print(closure1() + closure2())

A:

11

B:

16

C:

17

D:

6

Answer: C

Each closure captures the value of x from its own outer function call, resulting in 6 + 11 = 17.

📖

What is the output of the following Python code?

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

A:

[1, 2, 3, 4, 5] [1, 2, 3, 4, 5] None

B:

[1, 2, 3] [1, 2, 3, 4, 5] None

C:

[1, 2, 3, 4, 5] [1, 2, 3] None

D:

[1, 2, 3] [1, 2, 3] None

Answer: A

x is a list with values [1, 2, 3]. y is the result of concatenating x with [4, 5]. z is the result of extending x with [4, 5], but it returns None. The values of x, y, and z are printed. Thus, the output is [1, 2, 3, 4, 5] [1, 2, 3, 4, 5] None.

📖

Questions for: Tricky Questions