Setpember 29th, 2021
Running into issues? Post on ed or come to Juliette's office hours.
In CS 106A, you will be writing your code on your computer using an application called PyCharm. PyCharm is what is known as an IDE, or Integrated Development Environment, which means that it allows us to edit our code, browse our files, run our programs and debug them, all in the same place. It's one of the most popular Python IDEs in the world, and used extremely commonly in industry. This handout is intended to take you through installing PyCharm on your own computer.
In order to be able to run Python programs on your computer, you need
to install a Python Interpreter. An interpreter is a program
that is capable of reading a
.py file that you have
written, and translating the Python code in that file to instructions
that your computer can easily execute. Begin by downloading Python:
Macs come with a version of Python installed, but this is an older version of Python. CS 106A requires the use of the newest version of Python, so make sure to follow these instructions even if you think you already have Python installed. To install Python, simply open the downloaded installer file and follow the default instructions.
Open the downloaded file. Before installing, there should be an option that says "Add Python 3.9 in PATH". Make sure to check this box. Then, continue installing normally.
To get started, download and install the community version of PyCharm:
.dmgfile and drag PyCharm into your Applications folder)
.exefile and install PyCharm, using all the default options.)
At the end of the PyCharm installation process, you will be taken to a welcome screen that looks like this:
Click 'Configure' and then open PyCharm's settings, like so:
In the Preferences window, click 'Project Interpreter', open the dropdown menu, and click 'Show All':
In the following Window, click the plus icon in the bottom left corner:
Click 'System Interpreter' in the sidebar. Depending on whether you've installed other versions of Python before, Python 3.9 may already be selected in the dropdown menu. If not, select Python 3.9 and then click 'OK' and 'OK' again. I know this picture says python 3.8, but yours should say 3.9 in the dropdown menu. Please select 3.9:
You should now be on a window that looks like this (although the contents of your list might look different and will have python 3.9 instead of 3.8):
Click 'OK' again to be taken back to the welcome page. You're now ready to test PyCharm!
PyCharm models a program as a 'project', which consists of one or more Python files, as well as any additional resources like images or text files. To get you familiar with working with and running progams in PyCharm, we've provided a sample project, which you can download here. To test out this project, and to gain familiarity with the PyCharm environment, download the sample project (on Windows, you'll need to manually unzip it by opening it in Windows Explorer and selecting 'Extract All') and open it in PyCharm (using the 'open' option on the first screen). Whenever you open projects in PyCharm, open the folder directly containing the files you want to edit as opposed to just the files themselves. Upon opening the project, you should be greeted by a window that looks like this:
Click 'Project' in the top left or use the
Command + 1 shortcut
to open the file explorer, and open
intro.py to pull up the editor:
You aren't required to read or understand this code (although you will be able to by the end of the quarter!) but note that this editor is where you'll be writing all your code this quarter. Now, to run your program, click 'Terminal' in the bottom left corner, which will pull up a new terminal pane in your PyCharm window:
We'll talk more about the terminal later in the quarter, but for now, know that the terminal is how you'll be running your Python programs throughout the quarter. To run your first Python program, type this into the terminal and press enter:
You should see output that looks like this:
Now, type the following command into the terminal:
python3 intro.py < YOUR NAME HERE >
For example, if your name is Juliette, you'd type
python3 intro.py Juliette. You
can type your full name if you'd prefer. You should now see output like this:
Congratulations! You're now done with the PyCharm setup process.
Our strong recommendation is to use Python 3.9, which can be installed in parallel with other versions of Python. This is the only version of Python we'll be supporting in this class. You must use at least Python 3.6.
If there's another environment that you're more comfortable with, you may use it, but the course staff will only provide support for issues in PyCharm. You must not modify any configuration files provided in assignment starter code.
can't open file intro.py: No such file or directory! What does this mean?
This most often happens when you open the incorrect file or folder in PyCharm. In this case, make sure to
pycharm_intro folder that directly contains
intro.py, rather than
intro.py itself or a folder containing
pycharm_intro. On Windows computer, you may
have a folder called
pycharm_intro with another folder inside it called
Make sure to open the inner folder.
To correct this error, open the 'File' menu and click 'Open'. Then, navigate to the correct
pycharm_intro folder and open it.
To verify that you are in the correct folder,
ls (that's a lowercase 'L')
dir into your terminal (the same place
python3 intro.py < YOUR NAME HERE > ).
This will show you a list of all the files in that folder, and
be in this list.
This is likely caused by an issue with how you set up the interpreter. To fix this, click 'Configure Python Interpreter', and set up the interpreter by following these steps until the 'Testing Pycharm' section.
The default interactive shell is now zsh. To update your account to use zsh, please run `chsh -s /bin/zsh. What should I do?
That's just an innocuous message, don't worry about it!
You might be using a slightly older version of MacOS. Try installing this version of PyCharm instead.
Try installing this version of PyCharm instead.
Course FAQs will be updated as we receive questions.