12 Must‑Know Python One‑Liners to Boost Your Coding Efficiency

Python is a popular programming language because its concise syntax makes coding enjoyable. This article introduces twelve impressive Python one‑liners that can save time and reduce code length.

1. One‑Line For Loop

This one‑liner lets you write a for loop on a single line, printing each element of a list.

# example code
mylist = [4, 6, 8, 1, 3]
for x in mylist: print(x)
# Output
4
6
8
1
3

2. One‑Line If‑Else (Ternary Operator)

Use Python’s ternary operator to evaluate a condition and return one of two values in a single expression.

# example code 1
myval = 24 if 5 < 2 else 40
print(myval)  # 40
# example code 2
myval = 22 if 3 < 6 else 80
print(myval)  # 22

3. One‑Line Function with lambda

Define quick anonymous functions using lambda, which can be called like regular functions.

# example
fun = lambda x: x % 2
print(fun(3))  # 1 / False
print(fun(2))  # 0 / True

4. One‑Line Variable Swapping

Swap two variables without a temporary placeholder using tuple unpacking.

# old method
v1 = 1
v2 = 2
temp = v1
v1 = v2
v2 = temp
print(v1, v2)  # 2 1
# new method
v1 = 1
v2 = 2
v1, v2 = v2, v1
print(v1, v2)  # 2 1

5. One‑Line List Summation

Use the built‑in sum function to add all elements of a list in a single line.

# example
mylist = [1, 2, 3, 4, 5]
print(sum(mylist))  # 15

6. One‑Line Nested Loops (Double Loop)

Compress a nested for loop into a single line using list comprehension.

# multi‑line loop
lst1 = [1, 2]
lst2 = ["x", "y"]
for x in lst1:
    for y in lst2:
        print(x, y)
# one‑line version
[print(x, y) for x in lst1 for y in lst2]

7. One‑Line Sorting

Sort a list of numbers or strings in one line with the sorted function.

# integer sorting
mylist = [5, 3, 1, 0, 2, 4]
print(sorted(mylist))  # [0, 1, 2, 3, 4, 5]
# string sorting
mylist = ["C", "A", "B"]
print(sorted(mylist))  # ['A', 'B', 'C']

8. One‑Line Multiple Assignment

Assign values to several variables simultaneously in a single statement.

# multi‑line method
a = 1
b = 2
c = 3
print(a, b, c)  # 1 2 3
# one‑line method
a, b, c = 1, 2, 3
print(a, b, c)  # 1 2 3

9. One‑Line Palindrome Check

Check whether a string or number is a palindrome using slicing.

# example
val = '121'
isPalindrome = val == val[::-1]
print(isPalindrome)  # True

10. One‑Line List Filtering (List Comprehension)

Filter elements of a list with a condition using list comprehension.

# example
mylist = [2, 4, 9, 10, 1, 11, 34, 56]
result = [x for x in mylist if x > 8]
print(result)  # [9, 10, 11, 34, 56]

11. One‑Line Dictionary Creation with enumerate

Create a dictionary that maps indices to list elements using enumerate.

# example
mylist = ["a", "b", "c", "d"]
mydict = dict(enumerate(mylist))
print(mydict)  # {0: 'a', 1: 'b', 2: 'c', 3: 'd'}

12. One‑Line String‑to‑Integer Conversion

Convert a list of numeric strings to integers using map.

# example
strlist = ["1", "2", "3", "4", "5"]
intlist = list(map(int, strlist))
print(intlist)  # [1, 2, 3, 4, 5]

These one‑liners showcase Python’s ability to express common tasks succinctly, helping developers write cleaner and more efficient code.