Short answer: To find the minimal list in a list of lists, you need to make two lists comparable. How? With the key argument of the min() function. The key argument is a function that takes one input (a list) and returns one output (a numerical value). The list with the smallest numerical value is … Read more
How to check if a Python string s1 contains another string s2? There are two easy ways to check whether string s1 contains string s2: You can try both methods in our interactive Python shell (just click “Run” to execute the code in your browser): Puzzle: Can you modify “Method 2” so that it also … Read more
Short answer: To find the maximal list in a list of lists, you need to make two lists comparable. How? With the key argument of the max() function. The key argument is a function that takes one input (a list) and returns one output (a numerical value). The list with the largest numerical value is … Read more
The Python backslash (‘\’) is a special character that’s used for two purposes: Try it yourself in our interactive Python shell (just click “Run”): The backslash \ is an escape character–if used in front of another character, it changes the meaning of this character. For example, the character ‘n’ is just that a simple character, … Read more
This tutorial shows you how to group the inner lists of a Python list of lists by common element. There are three basic methods: Group the inner lists together by common element. Group the inner lists together by common element AND aggregating them (e.g. averaging). Group the inner lists together by common element AND aggregating … Read more
There are different ways to create random graphs in Python. But first things first: What is a Graph? According to Merriam-Webster, a graph is “a collection of vertices and edges that join pairs of vertices According to Merriam-Webster, a graph”. For example, this is a graph: Every edge connects exactly two vertices. What is a … Read more
Short answer: To filter a list of lists for a condition on the inner lists, use the list comprehension statement [x for x in list if condition(x)] and replace condition(x) with your filtering condition that returns True to include inner list x, and False otherwise. Lists belong to the most important data structures in Python—every … Read more
In Python, __doc__ is a special attribute that stores a string defining the documentation for a module, class, method, or function. It’s typically derived from a docstring — the first statement in the defined block, enclosed in triple quotes — providing a convenient way to access descriptive texts about the code’s functionality. You can define … Read more
Python is the most popular programming language in the world. The most important data structure in the most important programming language is the list data structure. In this tutorial, you’ll learn how to copy a list of lists. But be careful—simply copying your list may not do what you expected it to do. Let’s dive … Read more
Python’s creator Guido van Rossum doesn’t like the map() function because it can be easily replaced with list comprehension which is not only faster but also more readable and shorter. Map() vs List Comprehension Here’s an example: Both lists list_1 and list_2 contain the same data: a series of squared values [0, 1, 4, 9, … Read more
Problem: Given a list of lists representing a data matrix with n rows and m columns. How to sum over the rows of this matrix? In this article, you’re going to learn different ways to accomplish this in Python. Let’s ensure that you’re on the same page. Here’s a graphical representation of the list of … Read more
What’s the best way to remove duplicates from a Python list of lists? This is a popular coding interview question at Google, Facebook, and Amazon. In this article, I’ll show you how (and why) it works—so keep reading! How to remove all duplicates of a given value in the list? Method 1: Naive Method Algorithm: … Read more