Powerful Python One-Liners

Here are some powerful Python one-liners with examples to help you understand how they work.

📝 Basic Operations

1. Swap Two Variables

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

The Ternary Operator

1. Check If a Number Is Even or Odd

   num = 7
   print("Even" if num % 2 == 0 else "Odd")  # Output: Odd
   

   another examples

    eligible = True if age >= 18 else False
    status = "Adult" if age >= 18 else "Minor"
   

   Basic Data Processing: Calculate Average Easily

    numbers = [10, 20, 30, 40, 50]  
    average = sum(numbers) / len(numbers) if numbers else 0  
    print(average)  # Output: 30.0
   

   This one-liner computes the average of a list, ensuring it doesn’t divide by zero if the list is empty. 🚀

2. Reverse a String

   text = "Python"
   print(text[::-1])  # Output: nohtyP
   

3. Splitting and Joining Strings

   words = "hello world".split()  # Output: ['hello', 'world']
   csv_words = "hello,world".split(',')  # Output: ['hello', 'world']
   sentence = " ".join(["hello", "world"])  # Output: 'hello world'
   

   These one-liners efficiently split a sentence into words using .split() and join a list of words back into a sentence using .join(). 🚀 —

🔢 List Operations

1. Find the Sum of a List

   numbers = [1, 2, 3, 4, 5]
   print(sum(numbers))  # Output: 15
   

2. Find the Maximum in a List

   nums = [3, 6, 2, 8, 4]
   print(max(nums))  # Output: 8
   

3. Create a List of Squares

   print([x**2 for x in range(1, 6)])  
   # Output: [1, 4, 9, 16, 25]
   

4. Flatten a Nested List

   nested = [[1, 2], [3, 4], [5, 6]]
   print([num for sublist in nested for num in sublist])  
   # Output: [1, 2, 3, 4, 5, 6]
   

📊 String Operations

1. Count Word Occurrences in a Sentence

   from collections import Counter
   sentence = "apple banana apple orange banana apple"
   print(Counter(sentence.split()))  
   # Output: Counter({'apple': 3, 'banana': 2, 'orange': 1})
   

2. Check if a String Is a Palindrome

   is_palindrome = lambda s: s == s[::-1]
   print(is_palindrome("madam"))  # Output: True
   

🔍 Filtering and Sorting

1. Filter Even Numbers from a List

   nums = [1, 2, 3, 4, 5, 6]
   print(list(filter(lambda x: x % 2 == 0, nums)))  
   # Output: [2, 4, 6]
   

1. Sort a List of Tuples by the Second Element

   tuples = [(1, 3), (2, 2), (4, 1)]
   print(sorted(tuples, key=lambda x: x[1]))  
   # Output: [(4, 1), (2, 2), (1, 3)]
   

⏳ Time and Date

1. Get Current Date and Time

   from datetime import datetime
   print(datetime.now().strftime("%Y-%m-%d %H:%M:%S"))
   # Output: 2025-03-22 14:30:45 (depends on current time)
   

🔢 Mathematical Tricks

1. Generate Fibonacci Sequence

   fib = lambda n: n if n <= 1 else fib(n-1) + fib(n-2)
   print([fib(i) for i in range(6)])  
   # Output: [0, 1, 1, 2, 3, 5]
   

2. Find Factorial Using math Module

   import math
   print(math.factorial(5))  # Output: 120
   

3. Calculate the Square Root

   print(math.sqrt(25))  # Output: 5.0
   

🔗 Dictionary and File Operations

1. Create a Dictionary of Squares

   squares_dict = {num: num**2 for num in range(5)}
   print(squares_dict)  
   # Output: {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
   

2. Create a Dictionary from Two Lists Using zip()

   keys = ['a', 'b', 'c']
   values = [1, 2, 3]
   my_dict = {k: v for k, v in zip(keys, values)}
   print(my_dict)  
   # Output: {'a': 1, 'b': 2, 'c': 3}
   

3. Read a File in One Line

   print(open("sample.txt").read())  
   # Output: (prints the file content)
   

4. File Handling: Read and Clean Lines Efficiently

   lines = [line.strip() for line in open('my_document.txt')]
   

   This one-liner reads all lines from a file, removes extra whitespace, and stores them in a list using list comprehension. 🚀

5. Merge Two Dictionaries

   dict1 = {'a': 1, 'b': 2}
   dict2 = {'b': 3, 'c': 4}
   merged = {**dict1, **dict2}
   print(merged)  
   # Output: {'a': 1, 'b': 3, 'c': 4}
   

Further learning

• Powerful Python One-Liners
• Python One-Liners to Help You Write Simple, Readable Code