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🧠 Why One-Liners Matter:

ne-liners help you:

Avoid writing 5 lines when 1 is enough

Think in a “Pythonic” way

Impress interviewers and fellow coders

Speed up problem-solving in competitive coding

🚀 Let’s Jump In!

Swap Two Variables (No Temp)

a, b = 10, 20
a, b = b, a
No need for a third variable.
Output: a = 20, b = 10

Reverse a String

rev = "python"[::-1]
Output: 'nohtyp'

Check If a Number is Even

is_even = lambda x: x % 2 == 0
Usage: is_even(4) → True

Get All Even Numbers in a List

evens = [x for x in range(20) if x % 2 == 0]
Output: [0, 2, 4, 6, ..., 18]

Flatten a 2D List

flat = [item for sublist in [[1,2], [3,4]] for item in sublist]
Output: [1, 2, 3, 4]

Count Frequency of Items in a List

from collections import Counter
freq = Counter(["a", "b", "a", "c", "b", "a"])
Output: {'a': 3, 'b': 2, 'c': 1}

Find Factorial in One Line

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

Get Unique Items From a List

unique = list(set([1, 2, 2, 3, 3, 4]))
Output: [1, 2, 3, 4]

Check if a String is a Palindrome

is_palindrome = lambda s: s == s[::-1]
Usage: is_palindrome("madam") → True

Print a Table in One Line

print('\n'.join([f"{i} x 5 = {i*5}" for i in range(1, 11)]))

Output:

1 x 5 = 5  
2 x 5 = 10  
...  
10 x 5 = 50

✅ Final Thoughts: These one-liners may look simple, but they teach you powerful concepts like:

List comprehensions

Lambda functions

Built-in libraries

Pythonic patterns