Atom Code Editor


At this point you should have Python installed and working via Anaconda. Now that you have the tools you need to run Python code, let’s get you some tools for writing it.

What is an IDE?

As you’ve now seen demonstrated in class, the main product programmers output — raw computer source code, is in essence a block of text in a specific language that adheres to very strict rules. To write code, all you need is a program that lets you write text and save it.

More specifically, it needs to be plain text — only characters, and no formatting. Word, OpenOffice, and Pages are rich text word processors; they are not suitable for writing code. So are TextEdit, WordPad, and Notes even though they’re simpler, they still emit rich text rather than plain text. You could in theory use a stripped-down basic text editor like Notepad or the plain-text mode in TextEdit. But in practice, you’ll be much better off using an editor specifically designed for software.

Why? Because a good code editor can do a lot for you besides save text. In the very beginning, the only references to language and code for a given programming lanaguage came in the form of thick books, allowing the user to enter sample programs by hand straight into a console on the computer. There was little room for error and essentially no help from the computer.

Today, it’s a different story, and there are countless different ways for developers and programmers to enter and edit source code on their computers. These “programming assistance programs” often fall under the umbrella of IDEs - or Integrated Development Environments. In addition to allowing you to enter text and save and load tiles, a good IDE can help with:

Different programmers, different companies and different organisations often have their own standardized choices for what IDEs to use, and as such new employees often spend significant time onboarding in order to get used to these chosen tools. The benefit is when everyone works in the same IDE and environment, it’s very easy to rule out bugs and issues related to a given environment or IDE as well as facilitating collaboration between developers.

The IDE we have chosen for this course is called Atom Text. We think it strikes a nice balance of being both powerful and easy-to-use. You may use any other text editor or IDE you feel comfortable with, but be aware we will not officially provide help with configuration or any issues pertaining to your choice.

Installing Atom

Atom is an open source text and code editor from the folks at GitHub. The interface is very straightforward as it lacks many of the more advanced code analysis tools that come by default with other IDEs, and thus make Atom a very good choice when first interfacing with code.

The first step is to go to


and press the “Download for XYZ”, where XYZ will be your current operating system. After downloading, proceed to install Atom as you would any other program (i.e. on Windows -> run the installer, macOS -> drag and drop to “Applications”).

At this point you should be able to open Atom and be greeted with what you see below! Go ahead and get started by pressing “Open Project”

Atom First Page

Congratulations! You now have Atom Text installed and are almost ready to move on!

Using Atom

You can use Atom like any other editor (e.g., Word, Pages, TextEdit, or Notepad); it has all of the usual commands to New, Open, Save, Save As, and Close files. But there’s another way to use it that can sometimes be convenient if you’re working on more than one file: project view. To use it,, press the “Open Project” button that you see at the top of the available things to do. Then browse to any folder om your computer.

Atom Views

Now, you should see the contents of this folder show up on the left in a tree view (i.e. each subfolder is further indented from its parent), and clicking on any of the files in this tree view will open that file for editing. Once you have made any changes, simply do Command+s or Ctrl+s to save the file. To create a new file, use the keyboard shortcut Command+n or Ctrl+n, or right click and select “New File” in the tree view.