Python Basics

The following will guide you and point to the nessescary resources to learn python and try some basic exercises.

Python Basics
1. Table of contents

Getting started

Make sure you have Anaconda downloaded and an IDE to write code in.

Using PyCharm

PyCharm is a dedicated Python Integrated Development Environment (IDE) providing a wide range of essential tools for Python developers, tightly integrated to create a convenient environment for productive Python, web, and data science development. You could download the package through this website: (https://www.jetbrains.com/pycharm/). It is free for students if you apply for their free educational license: (https://www.jetbrains.com/community/education/#students). Note that you would need to renew the license annually.

Python practice problems

See here (https://www.practicepython.org) for good python practice problems. Once you are comfortable with manipulating lists, for loops, and if/else statements, focus on the ASE practice problems. You will learn the more complicated stuff later.

Python Documentation

See here (https://docs.python.org/3/) for the documentation.

Some Specific Guidelines for Writing Code

Naming: Make sure your names for variables are descriptive. h_atom_dict is better than atom_dict or h_atoms
Comments: Code is read more often than it is run. Comments should be extensive and clear. Imagine you are seeing this code for the first time, do the comments explain everything? Use docstrings for functions and classes.
Use Python’s functionality to make code shorter, but don’t overdo it. For example Python’s list comprehension can help remove a for loop while still being readable. But, if you find yourself trying to combine several steps into a single line, stop. Break these steps over several lines and explain them with comments.
Start small, test, then build more. You may be confident that several lines of code you wrote will work as intended, but test them anyways. It is a nightmare to find a bug inside dozens of connected functions over hundreds of lines of code. Instead, build a small working part, then make sure it outputs what you expect on several test cases and make sure it integrates nicely with the rest of the program. Only then should you start writing something new.
Search for help, then ask for help. A lot of coding issues can be resolved by a websearch. If you are stuck, first search for solutions to your problem online. Usually this will resolve your issue within 20 minutes. If you are still stuck, it is important that you ask the group for help (this can save you a lot of time!). Message the group on Slack with your problem and attempted solutions. If that doesn’t work, ask someone to look over your code with you, oftentimes a new person will be able to see what you are missing.

High Level Python Guidelines

Summarized from materials covered in ECS 32B.

Object-oriented programming (OOP)

OOP is a coding style where we define both the type of the data structures and functions that can be applied to those data structures. This way of treating data structures as objects allows the programmers to build connections between different objects; for example, one inherits characteristics from another. Another advantage compared to sequential coding is that OOP enables programmers to dissect a problem into sections where we call them classes without constantly having to worry about the whole picture.

Data structures and algorithms

Understanding data structures, such as arrays, trees, heaps, graphs and Python built-ins, allows programmers to store information where it can be accessed efficiently (Beginner theorists may not be needing this as much as OOP)

Some Smaller Topics

Debug & Unit testing

Pycharm has fancy debugging tools that allow programmers to step into the code and update all local variables after executing each line of code. Unit testing is an essential part of OOP since it helps to verify that the parts of the program (functions) do return results that match our expectations. For that reason, the test cases are usually written along with the program.

Type hinting

Type hints are hints that are given to the variables; for example, the inputs and outputs of a function, regarding their data types. It is useful especially when multiple programmers are working on the same project.

Inheritance

Objects with similar properties can inherit characteristics from the parent object without rewriting everything from the parent object. For example, different types of zeolite objects such as MFI inherits from the zeolite class. The child objects can also override the methods inherited from the parent.