Top Python Interview Questions

Q1. What is the maximum possible length of an identifier?

a) 31 characters

b) 63 characters

c) 79 characters

d) none of the mentioned

 Answer: d

Explanation: Identifiers can be of any length.

Q2. Why are local variable names beginning with an underscore discouraged?

a) they are used to indicate a private variable of a class

b) they confuse the interpreter

c) they are used to indicate global variables

d) they slow down execution

 Answer: a

Explanation: As Python has no concept of private variables, leading underscores are used to indicate variables that must not be accessed from outside the class.

Q3. What is the output of print 0.1 + 0.2 == 0.3?

a) True

b) False

c) Machine dependent

d) Error

Answer: b

Explanation: Neither of 0.1, 0.2 and 0.3 can be represented accurately in binary. The round off errors from 0.1 and 0.2 accumulate and hence there is a difference of 5.5511e-17 between (0.1 + 0.2) and 0.3

Q4. What is the result of round(0.5) – round(-0.5)?

a) 1.0

b) 2.0

c) 0.0

d) None of the mentioned

 Answer: b

Explanation: Python rounds off numbers away from 0 when the number to be rounded off is exactly halfway through. round(0.5) is 1 and round(-0.5) is -1.

Q5. What is the output of the following expression if x=456?

 print("%-06d"%x)

a) 000456

b) 456000

c) 456

d) error

 Answer: c

Explanation: The expression shown above results in the output 456.

Q6. What is the output of the following?

 i = 0

while i < 3:

    print(i)

    i += 1

else:

    print(0)

 a) 0 1 2 3 0

b) 0 1 2 0

c) 0 1 2

c) error

 Answer: b

Explanation: The else part is executed when the condition in the while statement is false

Q7. What is the output of the following?

 x = "abcdef"

i = "a"

while i in x[:-1]:

    print(i, end = " ")

 a) a a a a a

b) a a a a a a

c) a a a a a a …

d) a

 Explanation: String x is not being altered and i is in x[:-1].

Q8. What is the output of the following?

 print('ab12'.isalnum())

a) True

b) False

c) None

d) Error

Answer: a

Explanation: The string has only letters and digits.

Q9. Suppose listExample is [3, 4, 5, 20, 5, 25, 1, 3], what is list1 after list example.pop()?

a) [3, 4, 5, 20, 5, 25, 1].

b) [1, 3, 3, 4, 5, 5, 20, 25].

c) [3, 5, 20, 5, 25, 1, 3].

d) [1, 3, 4, 5, 20, 5, 25].

 Answer: a

Explanation: pop() by default will remove the last element.

 Q10. What is the output of the code shown below?

 l1=[1,2,3]

l2=[4,5,6]

[x*y for x in l1 for y in l2]

a) [4, 8, 12, 5, 10, 15, 6, 12, 18]

b) [4, 10, 18]

c) [4, 5, 6, 8, 10, 12, 12, 15, 18]

d) [18, 12, 6, 15, 10, 5, 12, 8, 4]

 Answer: c

Explanation: The code is shown above returns x*y, where x belongs to the list l1 and y belongs to the list l2. Therefore, the output is: [4, 5, 6, 8, 10, 12, 12, 15, 18].

Q11. Which of the following statements create a dictionary?

a) d = {}

b) d = {“john”:40, “peter”:45}

c) d = {40:”john”, 45:”peter”}

d) All of the mentioned

 Answer: d

Explanation: Dictionaries are created by specifying keys and values.

 Q12. What is the output of the below program?

 lamb = lambda x: x ** 3

print(lamb(5))

 a) 15

b) 555

c) 125

d) None of the mentioned

 Answer: c

Q13. What is the value returned by Math.floor(3.4)?

a) 3

b) 4

c) 4.0

d) 3.0

 Answer: a

Explanation: The floor function returns the biggest number that is smaller than or equal to the number itself.

 Q14. What is the output of the code shown below?

 l=[2, 3, [4, 5]]

l2=l.copy()

l2[0]=88

l

l2

 a) [88, 2, 3, [4, 5]]

[88, 2, 3, [4, 5]]

 b) [2, 3, [4, 5]]

[88, 2, 3, [4, 5]]

 c) [88, 2, 3, [4, 5]]

[2, 3, [4, 5]]

 d) [2, 3, [4, 5]]

[2, 3, [4, 5]]

 Answer: b

Explanation: The code shown above depicts a deep copy. In a deep copy, the base address of the objects is not copied. Hence the modification done on one list does not affect the other list.