Python Interview Questions

Python Interview Quiz

Difficulty: All Basic Medium Difficult Topic: All Syntax Functions Operators Exceptions List Comprehension

1. What is the default secondary prompt for continuation lines in Python's interactive mode?
A) ...
B) >>
C) ..
D) >>>

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2. How do you copy an object in Python?
A) Use deepcopy() only
B) Use copy.copy() or copy.deepcopy()
C) Use object.copy()
D) Use clone()

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3. What will be the output of `3 / 2` in Python 3?
A) 1.5
B) Error
C) 2
D) 1

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4. What is the output of this code?

list1 = [1, 3, 5, 7, 9]
list2 = [0, 2, 4, 6, 8]
print({x: y for x in list1 for y in list2})

A) {1: 0, 3: 2, 5: 4, 7: 6, 9: 8}
B) {1: [0, 2, 4, 6, 8], 3: [0, 2, 4, 6, 8], ...}
C) {0: 1, 2: 3, 4: 5, 6: 7, 8: 9}
D) {1: 8, 3: 8, 5: 8, 7: 8, 9: 8}

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5. Which pair best illustrates an abstract-concrete class relationship?
A) Colour - Red
B) Cat - Kitten
C) Truck - Window
D) Planet - Moon

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6. What is the purpose of PYTHONPATH, and how do you modify it?
A) PYTHONPATH is used to set the Python interpreter's version.
B) PYTHONPATH is an environment variable for module search paths.
C) PYTHONPATH is used to set the default encoding.
D) PYTHONPATH is used to define virtual environments.

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7. How do you remove leading whitespaces from a string in Python?
A) Use string.replace(' ', '')
B) Use string.lstrip()
C) Use string.rstrip()
D) Use string.strip()

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8. How do you comment multiple lines in Python?
A) Use for comments.
B) Use triple quotes or # on each line.
C) Use // for multi-line comments.
D) Use /* */ for multi-line comments.

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9. Given an array of 99 unique numbers from 1 to 100, how do you find the missing number, and what is the run time?
A) Subtract the sum of the array from 5050 in O(n) time.
B) Sort the array and find the missing number in O(n log n) time.
C) Use binary search to find the missing number in O(log n) time.
D) Use a hash set to find the missing number in O(n) time.

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10. How is Python an interpreted language?
A) Python is interpreted line-by-line.
B) Python is just-in-time compiled.
C) Python is transpiled to another language.
D) Python is compiled to machine code.

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11. What is the output of this code?

lst1 = [1, 2, 3]
lst2 = lst1
lst3 = lst2
del lst2[1:2]
print(lst3)

A) []
B) [1, 2, 3]
C) [1, 3]
D) [2, 3]

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12. What is the output of this code?

def pair_the_items():
    item_stack = [1, 2, 3, 4]
    idx = 0
    item_pairs = zip(item_stack[idx:-1], item_stack[idx+1:])
    print(type(item_pairs))
    print(f'item pairs: {list(item_pairs)}')
pair_the_items()

A) item pairs: [(1, 2), (2, 3), (3, 4)]
B) item pairs: [(1, 2, 3, 4)]
C) item pairs: [(1, 2), (2, 3), (3, 4)]
D) item pairs: (1, 2, 3, 4)

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13. How do you insert an object at a given index in Python?
A) Use list.add(index, object)
B) Use list.insert(index, object)
C) Use list.append()
D) Use list[index] = object

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14. How do you get the current working directory in Python?
A) import pwd; pwd()
B) import os.path; os.path.getcwd()
C) import sys; sys.getcwd()
D) import os; os.getcwd()

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15. What is the output of the following code?

class Foo(object):
    def __init__(self):
        self.x = 5
        self.bubbles = 2
class Buzz(Foo):
    def __init__(self):
        Foo.__init__(self)
        self.bubbles = 'Bubbles'
foo = Foo()
print(foo.x)
print(foo.bubbles)
buzz = Buzz()
print(buzz.x)
print(buzz.bubbles)
foo.x = 22
print(buzz.x)
print(Foo.bubbles)
Foo.bubbles = 'dasf'
print(foo.bubbles)
print(foo.x)

A) 5 2 5 'Bubbles' 5 2 'dasf' 22
B) 5 2 5 'Bubbles' 22 AttributeError
C) 5 2 5 'Bubbles' 5 AttributeError
D) 5 2 5 'Bubbles' 22 2 'dasf' 22

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16. How do you remove values from a Python array?
A) Use list.pop(index) to remove by index.
B) All of the above.
C) Use del list[index] to remove by index.
D) Use list.remove(value) to remove by value.

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17. What is the value of z after this code? x = 1 y = 0 z = 0 result = 2 try: z = z + 1 result = x / y z = z + 1 except ZeroDivisionError: z = z + result else: z = z + 1 finally: z = z + 1 z = z + 1 print(z)
A) 6
B) 3
C) 5
D) 4

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18. What happens when you multiply a list containing a sublist and modify it?
A) Each sublist is independent, so modifying one does not affect others.
B) All sublists are references to the same list, so modifying one affects all.
C) List multiplication creates deep copies of the sublist.
D) Modifying a sublist will raise an error.

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19. What happens when you access x[3] in a list with only 3 elements?
A) It returns None.
B) It returns the last element.
C) It wraps around to the first element.
D) It raises an IndexError.

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20. Which utility is used to install or remove Python packages?
A) sudo
B) pep
C) pip
D) yum

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21. Which statement best describes the Memento and Observer design patterns?
A) Memento alters an object's behavior when its state changes. Observer encapsulates an algorithm inside a class.
B) Memento defers the exact steps of an algorithm to a subclass. Observer defines a new operation.
C) Memento captures and restores an object's internal state, whereas Observer notifies multiple classes of changes.

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22. What is the purpose of the property decorator in Python?
A) The property decorator is used to define static methods.
B) The property decorator allows methods to be accessed as attributes.
C) The property decorator is used to handle exceptions.
D) The property decorator is used to create class methods.

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23. What does the `lambda` keyword do in Python?
A) Declares a loop.
B) Defines a named function.
C) Creates an anonymous function.
D) Imports a module.

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24. What is the output of `[x for x in range(5) if x % 2 == 0]`?
A) [2, 4]
B) [1, 3]
C) [0, 2, 4]
D) [0, 1, 2, 3, 4]

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25. How do you sort a list of dictionaries by 'lastName' in place?
A) sorted(my_list, key=lambda d: d['lastName'])
B) my_list.sort(key=d['lastName'])
C) my_list.sort(key=lambda d: d['lastName'])
D) sorted(my_list, key=d['lastName'])

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26. How do you remove whitespaces from a string in Python?
A) Use string.lstrip() and string.rstrip()
B) All of the above
C) Use string.strip()
D) Use string.replace(' ', '')

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27. Does Python have OOP concepts?
A) Python only supports procedural programming.
B) No, Python does not support OOP concepts.
C) Python supports OOP but not inheritance.
D) Yes, Python supports OOP concepts.

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28. What are list and dictionary comprehensions in Python? How do you create them and filter items?
A) Comprehensions are used to create functions.
B) Comprehensions are used for exception handling.
C) Comprehensions provide a concise way to create lists or dictionaries with optional filtering.
D) Comprehensions are used to define classes.

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29. What is the difference in variable scope between Python 2 and Python 3 in list comprehensions?
A) There is no difference in variable scope between Python 2 and Python 3.
B) In Python 2, list comprehensions leak variables; in Python 3, they do not.
C) In Python 2, list comprehensions do not leak variables; in Python 3, they do.
D) List comprehensions are not supported in Python 2.

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30. What are the results of 5/2, 5.0/2, and 5*1.0/2 in Python?
A) 2, 2.5, 2.5
B) 2, 2, 2.5
C) 2.5, 2, 2.5
D) 2.5, 2.5, 2.5

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31. In Python's interactive mode, which variable holds the value of the last printed expression?
A) *
B) -
C) _
D) ?

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32. Which expression represents 10 to the power of 3 in Python?
A) 10 * 3
B) 10 ** 3
C) 10 (3)
D) 10 ^ 3

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33. How do you use Abstract Base Classes (ABCs) in Python, and in what contexts are they suitable?
A) ABCs define a common interface for subclasses to implement specific methods.
B) ABCs are used to create concrete classes.
C) ABCs are used to handle exceptions.
D) ABCs are used for metaprogramming.

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34. What happens when you append to a list while iterating over it in Python?
A) It raises a RuntimeError.
B) It removes elements instead of appending.
C) It works fine and appends elements correctly.
D) It can lead to infinite loops or errors.

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35. What is the difference between a list and a tuple in Python?
A) Lists are immutable, tuples are mutable.
B) Both are immutable.
C) Lists are mutable, tuples are immutable.
D) Both are mutable.

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36. What is a key difference between Python 2 and Python 3 regarding the print statement?
A) Python 2 doesn't support print statements.
B) In Python 3, print is a function and requires parentheses.
C) Python 2 uses print() while Python 3 uses printf().
D) There is no difference; print works the same in both.

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37. What is the purpose of *args and **kwargs in Python?
A) *args is for named arguments, **kwargs for unnamed arguments.
B) *args is for keyword arguments, **kwargs for positional arguments.
C) *args is for default arguments, **kwargs for variable arguments.
D) *args is for positional arguments, **kwargs for keyword arguments.

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38. How do you delete a file in Python?
A) Use shutil.remove('filename')
B) Use os.delete('filename')
C) Use os.remove('filename')
D) Use file.delete('filename')

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39. How do you sort a list of dictionaries by multiple keys, such as 'lastName' and then 'firstName'?
A) sorted(my_list, key=lambda d: (d['lastName'], d['firstName']))
B) my_list.sort(key=lambda d: d['lastName'], d['firstName'])
C) sorted(my_list, key=[d['lastName'], d['firstName']])
D) sorted(my_list, key=lambda d: d['lastName'] + d['firstName'])

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40. What are Python functions?
A) Functions are used for exception handling.
B) Functions are reusable blocks of code that perform a specific task.
C) Functions are used for creating classes.
D) Functions are used for looping.

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41. What is the output of print(name[-1]) if name = 'Python'?
A) Invalid Syntax
B) P
C) End-of-lines
D) n

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42. Which of these is NOT a valid way to handle exceptions in Python?
A) catch-throw
B) try-finally
C) try-except-else
D) try-except

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43. What is the output of the following code and why?

class Foo:
    def __init__(self):
        self.x = 5
        self.bubbles = "Bubbles"
    def buzz(self):
        print(self.bubbles)
f = Foo()
f.buzz()

A) False, because a new list is created.
B) False, because the ids are different.
C) True, because the function returns the id of a new list.
D) True, because the list is modified in place.

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44. How do you create a Unicode string in Python?
A) Use u'text' in Python 3.
B) Use b'text' for Unicode strings.
C) Use 'text'.encode('utf-8')
D) All strings are Unicode in Python 3.

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45. What is the output of sorting this array alphabetically by food name and then by number?

foods = ['Apple-1', 'Cucumber-5', 'Apple-33', 'Banana-17', 'Strawberry-15', 'Strawberry-4', 'Apple-4', 'Coconut-7', 'Banana-18', 'Strawberry-23']

A) ['Strawberry-4', 'Strawberry-15', 'Strawberry-23', 'Coconut-7', 'Cucumber-5', 'Banana-17', 'Banana-18', 'Apple-1', 'Apple-4', 'Apple-33']
B) ['Cucumber-5', 'Coconut-7', 'Banana-18', 'Banana-17', 'Apple-33', 'Apple-4', 'Apple-1', 'Strawberry-23', 'Strawberry-15', 'Strawberry-4']
C) ['Apple-1', 'Apple-4', 'Apple-33', 'Banana-17', 'Banana-18', 'Coconut-7', 'Cucumber-5', 'Strawberry-4', 'Strawberry-15', 'Strawberry-23']
D) ['Apple-1', 'Apple-33', 'Apple-4', 'Banana-17', 'Banana-18', 'Coconut-7', 'Cucumber-5', 'Strawberry-15', 'Strawberry-23', 'Strawberry-4']

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46. What is the value of z after this code? z = 5 x = '456' while z > -1: y = x if y in ('1', '2', '3') or len(y) > 1: break x = x + y if y in ('4', '5', '6'): continue z = z - 1 print(z)
A) 0
B) -1
C) 5
D) 10

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47. What is a generator in Python, and where might you use one?
A) Generators yield values one at a time and are memory-efficient.
B) Generators are used for exception handling.
C) Generators are used for creating lists.
D) Generators are used for parallel processing.

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48. How do you create a nested comprehension in Python, and how does it compare to traditional for loops?
A) Nested comprehensions are not supported in Python.
B) Nested comprehensions are used for exception handling.
C) Nested comprehensions use multiple for loops in a single statement and are more concise but can be less readable.
D) Nested comprehensions are less concise than for loops.

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49. How does Python's garbage collection work, and what is the `gc` module?
A) Python does not have garbage collection.
B) Python uses reference counting and a cyclic garbage collector.
C) Python uses mark-and-sweep garbage collection.
D) Python uses a stop-the-world garbage collector.

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50. How can you set up a database in Django?
A) Edit settings.py and run 'python manage.py migrate'
B) Edit admin.py and run 'python manage.py createdb'
C) Edit urls.py and run 'python manage.py makemigrations'
D) Edit models.py and run 'python manage.py syncdb'

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51. What is the output of this code?

d1 = {}
d1['a'] = 1
d1['b'] = 2
d2 = d1
d2['a'] = 10
print(d1)
print(d2)

A) {'a': 1, 'b': 2} {'a': 1, 'b': 2}
B) {'a': 10, 'b': 2} {'a': 10, 'b': 2}
C) {'a': 1, 'b': 2} {'a': 10, 'b': 2}
D) {'a': 10} {'a': 10}

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52. How can we make forms in Python?
A) Use Django or Flask for web forms, Tkinter for GUI forms.
B) Use Flask for GUI forms, Tkinter for web forms.
C) Use PyQt for web forms, Django for GUI forms.
D) Use SQLAlchemy for forms.

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53. What is a reference to an object in Python?
A) It is the address where the variables and methods of an object are stored.
B) It is the physical address of an object.
C) It is the address of a variable only; not the methods of an object.
D) It is a shallow pointer that contains the address of an object.

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54. How are arguments passed by value or by reference in Python?
A) By reference
B) By object reference
C) By value
D) By name

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55. What happens when you use the += operator on a list with a string in Python?
A) It concatenates the string to the list as a single element.
B) It raises a TypeError.
C) It replaces the list with the string.
D) It appends each character of the string to the list.

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56. What is wrong with the following code?

odd = lambda x: bool(x % 2)
numbers = [n for n in range(10) if odd() if not odd(n)]
for i in range(len(numbers)):
    if odd(numbers[i]):
        del numbers[i]
print(numbers)

A) The list comprehension is incorrect, and the loop will cause a MemoryError.
B) The lambda function is used incorrectly, and the list comprehension has a syntax error.
C) The list comprehension is correct, but deleting items while iterating causes index errors.
D) The code is correct and will run without errors.

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57. How is memory managed in Python?
A) Python uses reference counting and garbage collection.
B) Python uses manual memory management.
C) Python uses a mark-and-sweep algorithm.
D) Python does not manage memory.

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58. Which built-in types in Python are mutable and which are immutable?
A) Mutable: list, tuple, set; Immutable: dict, frozenset, str
B) Mutable: dict, set, tuple; Immutable: list, frozenset, str
C) Mutable: list, dict, tuple; Immutable: set, frozenset, str
D) Mutable: list, dict, set; Immutable: tuple, frozenset, str

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59. What is the output of this code? from string import * method = 'METHODS' def x(methods): method = str.swapcase(methods) print(('%(method)s' % locals())) methods = str.swapcase(method[:-1]) x(methods)
A) 'METHOD'
B) 'Methods'
C) 'methods'
D) 'method'

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60. How do you count the occurrences of each character in a string and return the result as a dictionary?
A) Use a list to store counts.
B) Use a tuple to store character frequencies.
C) Use a set to count occurrences.
D) Use a dictionary with setdefault or defaultdict.

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61. What is the purpose of Python decorators, and how can they be used?
A) Decorators are used to create anonymous functions.
B) Decorators are used to define classes.
C) Decorators are used to extend function logic by handle redundant code among multiple functions by wrapping them.
D) Decorators are used to import functions and decorate them.

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62. How do you debug a Python program?
A) Use assert statements.
B) Use try-except blocks.
C) Use logging or traceback.
D) Use print statements or pdb.

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63. What is the output of this code? a = {1, 2, 3, 4} b = {2, 3, 4, 5} c = {3, 4, 5, 6} d = {4, 5, 6, 7} v = a.union(b, c) print(v | d)
A) {4, 5, 6, 7}
B) {1, 2, 3, 4, 5, 6, 7}
C) {1, 2, 3, 4}
D) {1, 2, 3, 4, 5, 6}

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64. How can you generate random numbers in Python?
A) Use the numpy module.
B) Use the statistics module.
C) Use the math module.
D) Use the random module.

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65. How do you install Python on Windows and set the path variable?
A) Download from GitHub and manually set the path.
B) Download from python.org and check 'Add Python to PATH'.
C) Use pip to install Python.
D) Install via Anaconda.

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66. Which statement is used to force a particular exception to occur in Python?
A) except
B) throws
C) raise
D) throw

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67. What is the output of this code? d = {'k1': 'alpha'} d.update(key3='gamma') d.update({'k1': 'delta'}) print(d)
A) {'k1': 'alpha'}
B) {'k1': 'alpha', 'key3': 'gamma'}
C) {'k1': 'gamma', 'key3': 'delta'}
D) {'k1': 'delta', 'key3': 'gamma'}

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