To install SymPy in Python, simply run the following command in your shell: This works for all major operating systems (MacOS, Windows, Linux). A preliminary is to have the pip package manager installed. (Confused by all the libraries, modules, pip, and virtual environments? Read the ultimate library guide on my blog.) To check whether it … Read more
Did you already try to sort a list of tuples? And when you saw the result, it wasn’t quite what you expected? Well, this happened to me when I went deeper into Python, and I suppose it also happened to you since you are looking for a solution. To me, this shows that you are … Read more
Programming is a humbling experience. Seemingly simple things will often surprise you, they’re not so trivial after all. One such example is the string to list conversion. In this article, you’ll learn everything you need to know to convert a string to a list—in different contexts and using different methods. Method Description list(string) Break a … Read more
A lambda function is an anonymous function in Python. It starts with the keyword lambda, followed by a comma-separated list of zero or more arguments, followed by the colon and the return expression. For example, lambda x, y, z: x+y+z would calculate the sum of the three argument values x+y+z. Here’s a practical example where … Read more
Are you confusing about SQLite Python Placeholders? It’s time for better understanding! Learn how in this tutorial. Introduction SQLite is an embedded open-source relational database engine. Its developers, from SQLite.org, call it a self-contained, serverless, zero-configuration, fast, reliable and transactional SQL database engine. It keeps things simple. SQLite “just works.” The SQLite library is also … Read more
Do you want to find the maximum of a Python list? This article gives you everything you need to know to master the max() function in Python. Description Python’s built-in max() function returns the maximum element of a list or its generalization (an iterable). Syntax The syntax of the max() function is as follows: Arguments … Read more
Today, let’s discuss something that’s all over the place in many code bases: what does if __name__ == ‘__main__’ do in Python? The statement if __name__ == ‘__main__’: checks if variable __name__ is set to the string value ‘__main__’ which holds only within the main source file from which you initially execute your code. In all other … Read more
Quick Article Summary to get a specific element from a list: Get elements by index use the operator [] with the element’s index use the list’s method pop(index) use slicing lst[start:stop:step] to get several elements at once use the function itemgetter() from the operator module Get elements by condition use the filter() function use a … Read more
Summary: There are only three best ways to reverse the order of the list elements: list.reverse() — Best if you want to reverse the elements of list in place. list[::-1] — Best if you want to write concise code to return a new list with reversed elements. reversed(list) — Best if you want to iterate … Read more
Summary: To convert a dictionary to a list of tuples, use the dict.items() method to obtain an iterable of (key, value) pairs and convert it to a list using the list(…) constructor: list(dict.items()). To modify each key value pair before storing it in the list, you can use the list comprehension statement [(k’, v’) for … Read more
Problem: Given are two lists l1 and l2. You want to perform either of the following: 1. Boolean Comparison: Compare the lists element-wise and return True if your comparison metric returns True for all pairs of elements, and otherwise False. 2. Difference: Find the difference of elements in the first list but not in the … Read more
Short answer: The most Pythonic way to compute the difference between two lists l1 and l2 is the list comprehension statement [x for x in l1 if x not in set(l2)]. This works even if you have duplicate list entries, it maintains the original list ordering, and it’s efficient due to the constant runtime complexity … Read more