#Python list comprehension how to

The results of these calculations enter the new list. Then comes the expression or operation you'd like to perform and carry out on each value inside the current iterable.List comprehensions start and end with opening and closing square brackets.The general syntax for list comprehension looks like this: new_list = List comprehension is a fast, short, and elegant way to create lists compared to other iterative methods, like for loops. You may also need to create new lists from scratch, or create a new list based on the values of an already existing list. When you're analyzing and working with lists in Python, you'll often have to manipulate, modify, or perform calculations on every single item in the list, all at once. What is list comprehension in Python? A syntax overview append() method, to add the square to the new list, square_numbersīut there is a quicker and more succinct way to achieve the same results – by using list comprehension. #create a new,empty list to hold their squares You could again use a for loop, like so: #initial list of numbers What if you already have a list of numbers, but want to create a new list with their squares? append() method to add the numbers 0 - 4 to my_list #range(5) creates an iterable, starting from 0 up to (but not including) 5

#iterate over the numbers 0 - 4 using the range() function One way to create a list in Python is by using a for loop.įor example, you can use the range() function to create a list of numbers ranging from 0 - 4.

#Python list comprehension how to

Let's get started! How to use a for loop to create a list in Python

I'll also show plenty of code examples along the way. In this beginner-friendly article, I'll give an overview of how list comprehension works in Python. Lists are a helpful and frequently used feature in Python.Īnd list comprehension gives you a way to create lists while writing more elegant code that is easy to read.