Before you can execute Python programs on your computer, you'll first need to install the python command-line utility.
Over the past few years there has been a shift in the community from Python Version 2 to Python Version 3. This semester we will be using Python 3, exclusively. We might use different minor versions of Python 3 (like 3.6 or 3.7), depending on the third-party packages we need to use for any given project.
Anaconda provides a command-line utility called conda to help us manage different versions of Python. Before proceeding, please take a moment to install Anaconda and get familiar with conda.
When you are ready, create and activate a new Anaconda virtual environment, and execute the following commands inside that virtual environment.
To see if Python is already installed, and if so where:
# Mac Terminal:
which python
# Windows Command Prompt:
where pythonIf you see a filepath output, it means Python is installed at the location specified, so you can advance to the version detection instructions below. Otherwise, if you see an empty result or an error message, that usually means Python is not installed.
Let's see which version of Python is installed:
python --versionAfter Python is installed, you should be able to execute python commands.
If you type python and press "enter", you will enter an interactive Python console. When you are done using the Python console, shut it down with exit().
You can alternatively use the python utility to execute pre-written Python programs. To test this out, create a new project directory called "my-first-project" with a new file called my_script.py, and use your text editor to place inside the following contents:
# my_script.py
print("--------------------------")
print("HELLO FROM A PYTHON SCRIPT")
print("--------------------------")Make sure to save the file.
Then use the python utility to execute the script by specifying its filepath:
# using a relative filepath:
python my_script.py
# OR using an absolute filepath:
python path/to/my-first-project/my_script.py