Python 3’s asyncio module provides fundamental tools for implementing asynchronous I/O in Python. It was introduced in Python 3.4, and with each subsequent minor release, the module has evolved significantly. This tutorial contains a general overview of the asynchronous paradigm, and how it’s implemented in Python 3.7. Blocking vs Non-Blocking I/O The problem that asynchrony seeks to resolve is blocking I/O. By default, when your program accesses data from an I/O source, it waits for that operation to complete before […]

In this article, we’ll examine how to append content to an existing file using Python. Let’s say we have a file called helloworld.txt containing the text “Hello world!” and it is sitting in our current working directory on a Unix file system: $ cat ./helloworld.txt Hello world! Now assume we want to append the additional text “It’s good to have been born!” to the end of this file from a Python program. The first step is to obtain a reference […]

In this article, we’ll examine four ways to use Python to check whether a string contains a substring. Each has their own use-cases and pros/cons, some of which we’ll briefly cover here: 1) The in Operator The easiest way to check if a Python string contains a substring is to use the in operator. The in operator is used to check data structures for membership in Python. It returns a Boolean (either True or False) and can be used as […]

In this article, we’ll examine how to use the built-in Python zip() function. The zip() function is a Python built-in function that allows us to combine corresponding elements from multiple sequences into a single list of tuples. The sequences are the arguments accepted by the zip() function. Any number of sequences can be supplied, but the most common use-case is to combine corresponding elements in two sequences. For example, let’s say we have the two lists below: >>> vehicles = […]

In this article, we’ll examine how to strip characters from both ends of a string in Python. The built-in String type is an essential Python structure, and comes with a built-in set of methods to simplify working with text data. There are many situations in which a programmer may want to remove unwanted characters, i.e. strip certain characters, from either the beginning or ending of a string. The most common requirement is to strip whitespace (spaces, tabs, newline characters, etc.) […]

Introduction In Python, a module is a self-contained file with Python statements and definitions. For example, file.py, can be considered a module named file. This differs from a package in that a package is a collection of modules in directories that give structure and hierarchy to the modules. Modules help us break down large programs into small files that are more manageable. With modules, code reusability becomes a reality. Suppose we have a function that is frequently used in different […]