Python List Comprehensions: How to Clean Up Your Code

Python List Comprehensions: How to Clean Up Your Code

Photo: Wikimedia Commons Python list comprehensions make your code shorter and much easier to read. If you write three lines of code just to build a simple list, you are doing extra work for no good reason. You can combine that whole loop into one single line that looks clean and works fast. A list comprehension is just a short way to build a new list out of an old one. Instead of setting up a blank list, writing a for loop, and appending items one by one, you do it all inside standard square brackets. It saves you time, cuts down on bugs, and makes your Python files look like a pro wrote them. What Is a Python List Comprehension? Think about making a basic grocery list on paper. You look in your fridge, find the food items you ran out of, and write them down one by one. In code, you usually do this with a standard loop. You create a blank list variable, iterate over your data, check a condition, and put the good items into your new storage container. That basic pattern takes four or five …