*The single line of Python code is more powerful than you may expect. In fact, you can compress whole algorithms in a single line of Python code. In this tutorial, you’ll learn how to use the built-in map() function in Python to one-linerize a critical step that would otherwise take multiple lines of Python code: to modify each element in a given iterable. *

Python’s `map()`

function applies a specific function to each element in a given iterable. It takes two arguments:

**Function**: The function to apply on each element of an iterable. In most cases, it’s a lambda function to defined once and on the fly.**Iterable**: Each iterable element is modified according to the function defined in the first argument.

The result is a `map()`

object, an iterator that saves all mapped elements so that you can iterate over them.

Consider the following `map()`

one-liner that changes each element `x`

of a list to the value of `x+1`

:

print(list(map(lambda x: x + 1, [1, 2, 3]))) # [2, 3, 4]

You create a `map`

function applies the function to each element in the list and returns a new map object. This is converted back to a list using the `list(...)`

function.

Try it yourself in our interactive code shell:

**Exercise**: Change the one-liner to calculate the square number of each list element.

## Python One-Liners Book: Master the Single Line First!

**Python programmers will improve their computer science skills with these useful one-liners.**

*Python One-Liners* will teach you how to read and write “one-liners”: ** concise statements of useful functionality packed into a single line of code. **You’ll learn how to systematically unpack and understand any line of Python code, and write eloquent, powerfully compressed Python like an expert.

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Detailed explanations of one-liners introduce ** key computer science concepts **and

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*lambda functions***,**

*regular expressions***and**

*map***functions, and**

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*slice assignments*You’ll also learn how to:

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**advanced regular expressions**using*grouping*and*named groups*,*negative lookaheads*,*escaped characters*,*whitespaces, character sets*(and*negative characters sets*), and*greedy/nongreedy operators* - Understand a wide range of
**computer science topics**, including*anagrams*,*palindromes*,*supersets*,*permutations*,*factorials*,*prime numbers*,*Fibonacci*numbers,*obfuscation*,*searching*, and*algorithmic sorting*

By the end of the book, you’ll know how to ** write Python at its most refined**, and create concise, beautiful pieces of “Python art” in merely a single line.

*Get your Python One-Liners on Amazon!!*

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com that has taught exponential skills to millions of coders worldwide. He’s the author of the best-selling programming books Python One-Liners (NoStarch 2020), The Art of Clean Code (NoStarch 2022), and The Book of Dash (NoStarch 2022). Chris also coauthored the Coffee Break Python series of self-published books. He’s a computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.