[toc] Have you been wondering – “How to declare an array in Python?” Well, if your answer is yes, then you are at the right place to find your answers; as in this article, we are going to learn about the different ways of declaring an array in Python. Video Walkthrough A Quick Introduction to … Read more
❗ Problem Formulation: How to assign the first list element to the variable head and the remaining elements to the variable tail? Let’s have a look at the two most Pythonic solutions to this one-liner programming challenge! 🙂 Method 1: Unpacking and Multiple Assignment Given a list. The most Pythonic way to unpack the first … Read more
Problem Formulation Given a Python iterable such as a list or a string that can be accessed via slicing. How to use the slicing operation iter[start, stop, step] so that for given values for start, stop, and step the output is an iterable (slice) containing only the first and the last element of the iterable? … Read more
NaN stands for Not A Number. It is a placeholder to indicate the absence of value. One can think of it as a None or 0. It’s just that None or 0 belongs to a specific type. However, NaN doesn’t. We use NaN to represent missing data or the failure to perform some operation. While … Read more
This is a simple algorithm to find all the powersets of a given set. If you feel like you need to refresh your Python set skills, have a look at my complete guide to Python sets (with Harry Potter examples). Problem Formulation: Powerset What is the powerset of a given set s? The powerset is … Read more
In this article, you will learn how to convert a Pandas DataFrame into a list and vice versa. This operation can be useful whenever you just want to focus on a specific column of a DataFrame and you would like to have it as a simple list. Sometimes you might be interested in converting a … Read more
In this article, you’ll learn about a basic algorithm, every computer scientist must know: the binary search algorithm. I have drawn the code from my NoStarch programming introductory book Python One-Liners: Applications Binary Search The algorithm has important practical applications in many basic data structures such as sets, trees, dictionaries, bags, bag trees, bag dictionaries, … Read more
Python’s __reversed__ magic method implements the reversed() built-in function that returns a reverse iterator over the values of the given sequence such as a list, a tuple, or a string. Syntax __reversed__(self) Let’s have a look at an example next. Example In the following code, you create a Person class with one name attribute. The … Read more
Syntax and Definition The Python __contains__() magic method implements the membership operation, i.e., the in keyword. Semantically, the method returns True if the argument object exists in the sequence on which it is called, and False otherwise. For example, 3 in [1, 2, 3] returns True as defined by the list method [1, 2, 3].__contains__(3). … Read more
Abstract: You can easily add multiple values to a key in a Python dictionary using different methods. We’ll explain each of the possible methods in detail, and also show you how you can update and delete multiple values. Finally, we’ll show you how to add multiple values to a python dictionary by creating a function … Read more
Quicksort is not only a popular question in many code interviews – asked by Google, Facebook, and Amazon – but also a practical sorting algorithm that is fast, concise, and readable. Because of its beauty, you won’t find many introductions to algorithms that don’t discuss the Quicksort algorithm. In this one-liner tutorial, you’ll learn about … Read more
Let’s start by noting that the key assumption we will be making throughout this article is that the aim is to get the elements as values, not to count them – but return a list with the corresponding values. Lists are one of the most common data structures used in Python and are created using … Read more