Python Technical Interview Questions and Answers - Set 1 (50 Questions)

Prepare for your Python interviews with these 50 technical questions and answers. Includes simple explanations and code examples.

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Basics

1. What is Python?

Python is a high-level, interpreted programming language used for web development, data analysis, AI, and automation.

2. Is Python case-sensitive?

a = 5
A = 10
print(a, A)  # Output: 5 10

3. What are Python data types?

Common data types: int, float, str, list, tuple, set, dict

4. How do you check a variable’s type?

x = 10
print(type(x))  # 

5. What is Python’s memory management?

Python uses automatic memory management via reference counting and garbage collection.

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Control Flow

6. What is an if statement?

x = 10
if x > 5:
    print("x is greater than 5")

7. Difference between for and while loops?

for i in range(3): print(i)
i = 0
while i < 3: print(i); i += 1

8. What is break?

for i in range(5):
    if i == 3: break
    print(i)

9. What is continue?

for i in range(5):
    if i == 2: continue
    print(i)

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Functions

10. What is a Python function?

def greet(): 
    print("Hello")
greet()

11. What are *args and **kwargs?

def test(*args, **kwargs):
    print(args, kwargs)
test(1,2,3, name="Python")

12. What is a lambda function?

square = lambda x: x*x
print(square(5))  # Output: 25

13. What is recursion?

def factorial(n):
    return 1 if n==1 else n*factorial(n-1)
print(factorial(5))  # 120

14. What is a decorator?

def decorator(func):
    def wrapper():
        print("Before")
        func()
    return wrapper

@decorator
def hello():
    print("Hello")

hello()

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Data Structures

15. Difference between list and tuple?

List is mutable; tuple is immutable.

16. What is a set?

s = {1,2,2,3}
print(s)  # {1,2,3}

17. What is a dictionary?

d = {"name":"Alice", "age":25}
print(d["name"])

18. How to iterate a dictionary?

for key, value in d.items():
    print(key, value)

19. What is list comprehension?

squares = [x*x for x in range(5)]
print(squares)

20. Difference between shallow and deep copy?

import copy
lst = [[1,2],[3,4]]
shallow = copy.copy(lst)
deep = copy.deepcopy(lst)

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OOP

21. What is a class and object?

class Student:
    pass
s = Student()

22. What is inheritance?

class A: pass
class B(A): pass

23. What is polymorphism?

Polymorphism allows the same method name to behave differently in different classes.

24. What is encapsulation?

Encapsulation restricts access to variables using private attributes like _var or __var.

25. What is the __init__ method?

class A:
    def __init__(self, name):
        self.name = name
a = A("Python")

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Exceptions & File Handling

26. What is exception handling?

try:
    x = 10/0
except ZeroDivisionError:
    print("Cannot divide by zero")

27. What is finally?

try:
    x = 10
finally:
    print("Done")

28. How to read a file?

with open("test.txt","r") as f:
    print(f.read())

29. How to write a file?

with open("test.txt","w") as f:
    f.write("Hello")

30. How to handle multiple exceptions?

try:
    x = int("abc")
except (ValueError, TypeError) as e:
    print("Error:", e)

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Libraries & Modules

31. What is NumPy?

import numpy as np
arr = np.array([1,2,3])

32. What is Pandas?

import pandas as pd
df = pd.DataFrame({"A":[1,2],"B":[3,4]})

33. What is Matplotlib?

import matplotlib.pyplot as plt
plt.plot([1,2,3],[4,5,6])
plt.show()

34. What is JSON module?

import json
data = '{"name": "Alice"}'
parsed = json.loads(data)

35. What is OS module?

import os
print(os.getcwd())

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Coding Questions

36. Reverse a string

s = "Python"
print(s[::-1])

37. Check palindrome

s = "madam"
print(s == s[::-1])

38. Fibonacci series

a,b=0,1
for i in range(5):
    print(a)
    a,b = b,a+b

39. Count vowels in a string

text = "Python"
print(sum(1 for c in text if c in "aeiouAEIOU"))

40. Find max in a list

nums = [1,5,3]
print(max(nums))

41. Merge two lists

a = [1,2]
b = [3,4]
c = a+b

42. Remove duplicates from list

lst = [1,2,2,3]
print(list(set(lst)))

43. Sort a dictionary by value

d = {'a':3,'b':1}
print(dict(sorted(d.items(), key=lambda x: x[1])))

44. Check prime number

n=7
print(all(n%i!=0 for i in range(2,n)))

45. Find factorial

import math
print(math.factorial(5))

46. Read CSV file

import csv
with open("data.csv") as f:
    reader = csv.reader(f)
    for row in reader: print(row)

47. Write CSV file

with open("out.csv","w",newline="") as f:
    writer = csv.writer(f)
    writer.writerow([1,2,3])

48. HTTP request using requests

import requests
r = requests.get("https://api.github.com")
print(r.status_code)

49. Random number generation

import random
print(random.randint(1,10))

50. Check type of variable

x = [1,2,3]
print(isinstance(x,list))  # True

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