Course Home | Assignments | Data Sets/Tools | Python | Schedule | Git Submission | Tutoring

Saint Louis University

Computer Science 1020
Introduction to Computer Science: Bioinformatics

Michael Goldwasser

Spring 2019

Computer Science Department


Python is an open-source programming language that is freely-available for all major computing platforms. Something to be aware of is that there are two major versions of Python currently in use (the so called Python 2.x branch and Python 3.x branch). We will be using the 3.x line in this course (and it is not backward compatible with the 2.x branch).

If you are using your account on our department's hopper system, Python is already installed and can be started by typing the command python3 in a console window (not to be confused with the command python which is the default 2.x branch). There is also a development environment for Python known as IDLE that is available by navigating the start menu to Applications -> Development -> IDLE3.

We note that there is a bit of an inherent slowdown when running Python programs within IDLE rather than directly in the interpretter, so for large-scale computations it is often helpful to know how to run a script directly in the interpretter. This can be done through a typical commandline interface in a terminal window (or command prompt on Windows), with a command such as


Local Installation

If you wish to run locally on your own computer, Python can be easily installed. In fact, if you have an Apple computer, Python and IDLE are already pre-installed as part of the OSX distribution. You can open a terminal window and start Python by typing the command python, or IDLE by typing the command idle. For other platforms, you can download a Python installer from; make sure to download the Python 3.x line (Python 3.7.1 is the most current release as of October 2018).

Web-based Python Tools

While it will be helpful to have the Python interpreter installed on your own computer, there are actually many very good web-based tools that would provide you with either an interactive interpreter or even ways to execute Python scripts through a browser. Those are great both for exploring, and perhaps even for completing assignments. In the end, what you will typically be submitting for programming assignments is your source code, so if you can develop that on a web-based platform, that's okay.

Here are some sites that we can recommend:

Michael Goldwasser
CSCI 1020, Spring 2019
Last modified: Friday, 11 January 2019
Course Home | Assignments | Data Sets/Tools | Python | Schedule | Git Submission | Tutoring