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Samar Fatima Jaffri
Samar Fatima Jaffri

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Unleash Python's Magic: The Craft of One-Liner Code


Python is well-known for its clear and easy-to-read code, but there's one aspect that programmers find particularly fascinating: the one-liner code. This blog post will take you on a journey through the art of condensing complex functionality into a single line of Python code. We'll explore concise list comprehensions and elegant lambda functions, delving into their power, creativity, and efficiency. These one-liners can really pack a punch!

1. List Comprehensions:

The list comprehensions in Python are a great example of concise code. Turning loops into compact expressions, list comprehension allows for the creation and manipulation of lists in just one line of code.
Here is an example of generating a list of multiple of 2.

# ordinary way
multiples = []
for i in range(1, 10):
    multiples.append(i * 2)

# using list comprehension
multiples = [i * 2 for i in range(1, 10)]
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2. Lambda Functions:

Lambda functions, also known as anonymous functions, allow us to create concise functions in a single line. They are especially handy for performing straightforward tasks.
Let's see an example of an add function.

# ordinary way
def add(x, y):
    return x + y

# using lambda functions
add = lambda x, y: x + y
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3. Conditional Expressions:

With Python's ternary conditional expressions, you can use inline if-else statements to streamline your code. This results in a more elegant and concise code.
Let's take a simple example of finding if the number is even or odd.

num = int(input('Enter a number: '))

# ordinary way
if num % 2 == 0:
    result = 'Even'
    result = 'Odd'

# using condition expressions
result = 'Even' if num % 2 == 0 else 'Odd'
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4. Comma Operator:

As a Python developer, you'll find Python's Comma Operator to be an invaluable tool. It allows you to easily unpack iterables and swap values, saving both lines of code and memory.
Let's look at an example of swapping two variables.

a, b = 1, 2  # initializing two variables at once

# ordinary way
temp = a
a = b
b = temp

# using the comma operator
a, b = b, a
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5. Extended Slicing:

Extended slicing in Python can perform some magical tricks within the code. It's applicable to both lists and string values.
Let's see how it simplifies palindrome checks by revering string in one line.

s = 'abcba'

# ordinary way
reverse_s = ''
for char in s:
    reverse_s = char + reverse_s
is_palindrome = s == reverse_s

# using extended slicing
is_palindrome = s == s[::-1]
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6. Short Circuit Evaluation:

To return a value based on a condition, Short Circuit Evaluation is an effective approach. Python developers can use a one-liner code and employ and, or, or not for this purpose.
Let's see how we can use or for conditional expressions

val = 0
# ordinary way
if val:
    result = val
    result = 'Default Value'

# using short circuit evaluation
result = val or 'Default Value'
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7. Dictionary Comprehensions:

Similar to how we utilize list comprehensions, we can also form dictionaries through dictionary comprehensions.
Let's reuse the example of multiple of 2 for dictionary comprehension.

# ordinary way
multiples = dict()  # using dict() here as {} defines both empty set and dict
for i in range(1, 10):
    multiples[i] = i * 2

# using dictionary comprehension
multiples = {i: i * 2 for i in range(1, 10)}
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8. Strings Concatenation:

In all programming languages, there is a basic feature known as string concatenation. Although it may seem like a simple concept, it can actually be utilized to convert a list into a string. This is why it has been included in this list.
Let's look into it by taking an example of a list of words.

arr = ['Python', 'is', 'amazing!']
# ordinary way
str = ''
s = ''
for item in arr:
    s += item + ' '

# using string concatenation
s = ' '.join(arr)
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Downside of Using One-Liner

Although Python's one-liners can make code cleaner and more readable, overusing them can harm readability.
For instance, let's consider checking whether a number is positive, negative, or zero.

num = int(input('Enter a number: '))

# ordinary way
if num < 0:
    result = 'Negative'
elif num > 0:
    result = 'Positive'
    result = 'Zero'

# using condition expressions
result = 'Negative' if num < 0 else 'Positive' if num > 0 else 'Zero'
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In the example given, the conventional method is easier to understand than the one-liner conditional expression. Therefore, it is advisable to strike a balance between not using the one-liner and using it excessively, as both can impact code readability and even performance in certain situations.


Python's one-liner code snippets showcase the language's adaptability and expressiveness. However, it's crucial to ensure that the code remains easy to read and not overly complex despite its brevity. One-liners, used wisely, can improve code efficiency, simplify tasks, and add a touch of coding elegance. Therefore, if you're faced with a long-winded solution, consider whether a clever one-liner could be the perfect solution for your code.

Top comments (4)

hamzairshad02 profile image

While using one-liners sure is an efficient way of writing code it just sometimes becomes a headache for a code reviewer like me. Your last point in this article is on point about this very problem.

samarfatimajaffri profile image
Samar Fatima Jaffri

Absolutely, when one-liners are being an overkill, it's better to use traditional methods.

sreno77 profile image
Scott Reno

Very useful! Thanks

samarfatimajaffri profile image
Samar Fatima Jaffri

I am glad that you find it useful