50 Most Commonly Used Python Code Snippets for Everyday Programming

SummaryLearn essential Python code snippets for everyday programming, covering list operations, file handling, string manipulation, mathematical operations, data structures, conditionals, loops, utilities, modules, and advanced techniques. Discover how to perform tasks such as list comprehension, file reading and writing, string reversal, and data type checking. Explore snippets for calculating factorials, generating Fibonacci sequences, and working with dictionaries. Master useful functions like lambda, map, filter, and reduce, and improve your Python programming skills with these 50 commonly used code snippets.
Python, owing to its simplicity and expressiveness, remains one of the most loved programming languages in the world. Whether you are a beginner or a seasoned developer, having a handy set of frequently used code snippets can save considerable time. This article presents 50 widely used Python code snippets, categorised for clarity and practical use.
π List Operations
1. List Comprehension with Condition
squares = [x**2 for x in range(10) if x % 2 == 0]
2. Flatten a Nested List
nested = [[1, 2], [3, 4]]
flat = [item for sublist in nested for item in sublist]
3. Remove Duplicates from a List
unique_items = list(set(my_list))
4. Reverse a List
reversed_list = my_list[::-1]
5. Sort List of Dictionaries by Key
sorted_list = sorted(dicts_list, key=lambda x: x['key_name'])
π File Handling
6. Read a File
with open('file.txt', 'r') as file:
content = file.read()
7. Write to a File
with open('file.txt', 'w') as file:
file.write('Hello, World!')
8. Append to a File
with open('file.txt', 'a') as file:
file.write('\nAppended line.')
9. Read a File Line by Line
with open('file.txt', 'r') as file:
for line in file:
print(line.strip())
10. Check if File Exists
import os
exists = os.path.isfile('file.txt')
π String Manipulation
11. Reverse a String
reversed_str = my_string[::-1]
12. Check for Palindrome
is_palindrome = my_string == my_string[::-1]
13. Count Occurrences of a Substring
count = my_string.count('substring')
14. Replace Substring
new_string = my_string.replace('old', 'new')
15. Split String into List
words = my_string.split()
π Mathematical Operations
16. Calculate Factorial
import math
result = math.factorial(5)
17. Generate Fibonacci Sequence
def fibonacci(n):
a, b = 0, 1
for _ in range(n):
yield a
a, b = b, a + b
18. Check for Prime Number
def is_prime(n):
return n > 1 and all(n % i for i in range(2, int(n**0.5) + 1))
19. Find GCD of Two Numbers
import math
gcd = math.gcd(a, b)
20. Calculate Square Root
import math
sqrt = math.sqrt(16)
π Data Structures
21. Merge Two Dictionaries
merged_dict = {**dict1, **dict2}
22. Invert a Dictionary
inverted = {v: k for k, v in original.items()}
23. Create Dictionary from Two Lists
dict_from_lists = dict(zip(keys, values))
24. Count Frequency of Elements
from collections import Counter
freq = Counter(my_list)
25. Sort Dictionary by Value
sorted_dict = dict(sorted(my_dict.items(), key=lambda item: item[1]))
π§ͺ Conditionals and Loops
26. Ternary Conditional Operator
result = 'Yes' if condition else 'No'
27. Enumerate in Loop
for index, value in enumerate(my_list):
print(index, value)
28. Zip Multiple Lists
for a, b in zip(list1, list2):
print(a, b)
29. List Comprehension with Multiple Conditions
result = [x for x in range(100) if x % 2 == 0 and x % 5 == 0]
30. Nested Loops in List Comprehension
pairs = [(x, y) for x in list1 for y in list2]
π οΈ Utilities
31. Measure Execution Time
import time
start = time.time()
# code block
end = time.time()
print(f"Execution Time: {end - start}")
32. Shuffle a List
import random
random.shuffle(my_list)
33. Generate Random Number
import random
num = random.randint(1, 100)
34. Check if List is Empty
if not my_list:
print("List is empty")
35. Swap Two Variables
a, b = b, a
π¦ Modules and Packages
36. Install Package via pip
pip install package_name
37. Import Module with Alias
import numpy as np
38. Handle Import Errors
try:
import module
except ImportError:
# handle error
39. List Installed Packages
pip list
40. Get Current Working Directory
import os
cwd = os.getcwd()
π§° Advanced Techniques
41. Lambda Function
square = lambda x: x * x
42. Map Function
squares = list(map(lambda x: x**2, my_list))
43. Filter Function
evens = list(filter(lambda x: x % 2 == 0, my_list))
44. Reduce Function
from functools import reduce
product = reduce((lambda x, y: x * y), my_list)
45. List All Attributes of an Object
attributes = dir(object)
ποΈ Miscellaneous
46. Check Data Type
type_of_var = type(variable)
47. Convert String to Integer
num = int('123')
48. Convert Integer to String
s = str(123)
49. Format String with f-Strings
name = 'Alice'
greeting = f'Hello, {name}!'
50. Use of Any and All
any_true = any([False, True, False])
all_true = all([True, True, True])
These code snippets are practical, often used in day-to-day tasks, and should be part of every Python developer's toolkit. Feel free to bookmark or adapt them to your projects.