Python 3 Installation & Setup Guide

Limitations of the Microsoft Store Package

The official Python documentation has this to say about the Microsoft Store package:

The Microsoft Store package is an easily installable Python interpreter that is intended mainly for interactive use, for example, by students. (Source)

The key takeaway here is that the Microsoft Store package is “intended mainly for interactive use.” That is, the Microsoft Store package is designed to be used by students and people learning to use Python for the first time.

In addition to targeting beginning Pythonistas, the Microsoft Store package has limitations that make it ill-suited for a professional development environment. In particular, it does not have full write access to shared locations such as TEMP or the registry.

Windows Installer Recommendations

If you’re new to Python and focused primarily on learning the language rather than building professional software, then you should install from the Microsoft Store package. This offers the shortest and easiest path to getting started with minimal hassle.

On the other hand, if you’re an experienced developer looking to develop professional software in a Windows environment, then the official Python.org installer is the right choice. Your installation won’t be limited by Microsoft Store policies, and you can control where the executable is installed and even add Python to PATH if necessary.

Step 1: Open the Python App Page in the Microsoft Store

Open the Microsoft Store app and search for Python.

You’ll likely see multiple versions that you can choose to install:

Select Python 3.8, or the highest version number you see available in the app, to open the installation page.

Alternatively, you can open PowerShell and type the following command:

C:\> python

If you don’t already have a version of Python on your system, then when you press Enter, the Microsoft Store will automatically launch and take you to the latest version of Python in the store.

Step 2: Install the Python App

After you’ve selected the version to be installed, follow these steps to complete the installation:

1. Click Get.

2. Wait for the application to download. When it’s finished downloading, the Get button will be replaced with a button that says Install on my devices.

3. Click Install on my devices and select the devices on which you’d like to complete the installation.

4. Click Install Now and then OK to start the installation.

5. If the installation was successful, then you’ll see the message “This product is installed” at the top of the Microsoft Store page.

Congratulations! You now have access to Python, including pip and IDLE!

Step 1: Download the Full Installer

Follow these steps to download the full installer:

1. Open a browser window and navigate to the Python.org Downloads page for Windows.

2. Under the “Python Releases for Windows” heading, click the link for the Latest Python 3 Release - Python 3.x.x. As of this writing, the latest version was Python 3.8.4.

3. Scroll to the bottom and select either Windows x86-64 executable installer for 64-bit or Windows x86 executable installer for 32-bit.

If you aren’t sure whether to select the 32-bit or the 64-bit installer, then you can expand the box below to help you decide.

When the installer is finished downloading, move on to the next step.

Step 2: Run the Installer

Once you’ve chosen and downloaded an installer, run it by double-clicking on the downloaded file. A dialog box like the one below will appear:

There are four things to notice about this dialog box:

1. The default install path is in the AppData/ directory of the current Windows user.

2. The Customize installation button can be used to customize the installation location and which additional features get installed, including pip and IDLE.

3. The Install launcher for all users (recommended) checkbox is checked default. This means every user on the machine will have access to the py.exe launcher. You can uncheck this box to restrict Python to the current Windows user.

4. The Add Python 3.8 to PATH checkbox is unchecked by default. There are several reasons that you might not want Python on PATH, so make sure you understand the implications before you check this box.

The full installer gives you total control over the installation process.

Customize the installation to meet your needs using the options available on the dialog box. Then click Install Now. That’s all there is to it!

Congratulations—you now have the latest version of Python 3 on your Windows machine!

Limitations of Installing From Homebrew

The Python distribution for macOS available on Homebrew doesn’t include the Tcl/Tk dependency required by the Tkinter module. Tkinter is the standard library module for developing graphical user interfaces in Python and is in fact an interface for the Tk GUI toolkit, which isn’t part of Python.

Homebrew doesn’t install the Tk GUI toolkit dependency. Instead, it relies on an existing version installed on your system. The system version of Tcl/Tk may be outdated or missing entirely and could prevent you from importing the Tkinter module.

macOS Installer Recommendations

The Homebrew package manager is a popular method for installing Python on macOS because it’s easy to manage from the command line and offers commands to upgrade Python without having to go to a website. Because Homebrew is a command-line utility, it can be automated with bash scripts.

However, the Python distribution offered by Homebrew isn’t controlled by the Python Software Foundation and could change at any time. The most reliable method on macOS is to use the official installer, especially if you plan on doing Python GUI programming with Tkinter.

Step 1: Download the Official Installer

Follow these steps to download the full installer:

1. Open a browser window and navigate to the Python.org Downloads page for macOS.

2. Under the “Python Releases for Mac OS X” heading, click the link for the Latest Python 3 Release - Python 3.x.x. As of this writing, the latest version was Python 3.8.4.

3. Scroll to the bottom and click macOS 64-bit installer to start the download.

When the installer is finished downloading, move on to the next step.

Step 2: Run the Installer

Run the installer by double-clicking the downloaded file. You should see the following window:

Follow these steps to complete the installation:

1. Press Continue a few times until you’re asked to agree to the software license agreement. Then click Agree.

2. You’ll be shown a window that tells you the install destination and how much space it will take. You most likely don’t want to change the default location, so go ahead and click Install to start the installation.

3. When the installer is finished copying files, double-click the Install Certificates command in the finder window to make sure your SSL root certificates are updated.

Congratulations—you now have the latest version of Python 3 on your macOS computer!

Step 1: Install Homebrew

If you already have Homebrew installed, then you can skip this step. If you don’t have Homebrew installed, then use the following procedure to install Homebrew:

1. Open a browser and navigate to http://brew.sh/.

2. You should see a command for installing Homebrew near the top of the page under the tile “Install Homebrew.” This command will be something like the following:

   Shell

   $ /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
   

   Highlight the command with your cursor and press Cmd+C to copy it to your clipboard.

3. Open a terminal window and paste the command, then press Enter. This will begin the Homebrew installation.

4. Enter your macOS user password when prompted.

Depending on your Internet connection, it may take a few minutes to download all of Homebrew’s required files. Once the installation is complete, you’ll end up back at the shell prompt in your terminal window.

Now that Homebrew is installed, you’re ready to install Python.

Step 2: Install Python

Follow these steps to complete the installation with Homebrew:

1. Open a terminal application.

2. Type in the following command to upgrade Homebrew:

   Shell

   $ brew update && brew upgrade
   

Installing with Homebrew is now as straightforward as running the command brew install python3. This will download and set up the latest version of Python on your machine.

You can make sure everything went correctly by testing if you can access Python from the terminal:

1. Open a terminal.

2. Type pip3 and press Enter.

3. You should see the help text from Python’s pip package manager. If you get an error message running pip3, then go through the install steps again to make sure you have a working installation.

Congratulations—you now have Python on your macOS system!

Linux Installation Recommendations

The most popular way to install Python on Linux is with your operating system’s package manager, which is a good choice for most users. However, depending on your Linux distribution, Python may not be available through a package manager. In this case, you’ll need to build Python from source code.

There are three main reasons that you might choose to build Python from source code:

1. You can’t download Python from your operating system’s package manager.

2. You need to control how Python gets compiled, such as when you want to lower the memory footprint on embedded systems.

3. You want to try out beta versions and release candidates of the latest and greatest version before it’s generally available.

To complete the installation on your Linux machine, find your Linux distribution below and follow the steps provided.

Step 1: Download the Source Code

To start, you need to get the Python source code. Python.org makes this fairly straightforward. If you go to the Downloads page, then you’ll see the latest source for Python 3 at the top. Just make sure you don’t grab Legacy Python, Python 2!

When you select the Python 3 version, you’ll see a “Files” section at the bottom of the page. Select Gzipped source tarball and download it to your machine. If you prefer a command-line method, you can use wget to download the file to your current directory:

$ wget https://www.python.org/ftp/python/3.8.4/Python-3.8.4.tgz

When the tarball finishes downloading, there are a few things you’ll need to do to prepare your system for building Python.

Step 2: Prepare Your System

There are a few distro-specific steps involved in building Python from scratch. The goal of each step is the same on all distros, but you might need to translate to your distribution if it doesn’t use apt-get:

1. First, update your package manager and upgrade your packages:

   Shell

   $ sudo apt-get update
   $ sudo apt-get upgrade
   

2. Next, make sure you have all of the build requirements installed:

   Shell

   # For apt-based systems (like Debian, Ubuntu, and Mint)
   $ sudo apt-get install -y make build-essential libssl-dev zlib1g-dev \
          libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm \
          libncurses5-dev libncursesw5-dev xz-utils tk-dev
   
   # For yum-based systems (like CentOS)
   $ sudo yum -y groupinstall "Development Tools"
   $ sudo yum -y install gcc openssl-devel bzip2-devel libffi-devel
   

   It’s fine if you already have some of the requirements installed on your system. You can execute the above commands and any existing packages will not be overwritten.

Now that your system is ready to go, it’s time to start building Python!

Step 3: Build Python

1. Once you have the prerequisites and the TAR file, you can unpack the source into a directory. Note that the following command will create a new directory called Python-3.8.3 under the one you’re in:

   Shell

   $ tar xvf Python-3.8.4.tgz
   $ cd Python-3.8.4
   

2. Now you need to run the ./configure tool to prepare the build:

   Shell

   $ ./configure --enable-optimizations --with-ensurepip=install
   

   The enable-optimizations flag will enable some optimizations within Python to make it run about 10 percent faster. Doing this may add twenty or thirty minutes to the compilation time. The with-ensurepip=install flag will install pip bundled with this installation.

3. Next, you build Python using make. The -j option simply tells make to split the building into parallel steps to speed up the compilation. Even with the parallel builds, this step can take several minutes:

   Shell

   $ make -j 8
   

4. Finally, you’ll want to install your new version of Python. You’ll use the altinstall target here to avoid overwriting the system Python. Since you’re installing into /usr/bin, you’ll need to run as root:

   Shell

   $ sudo make altinstall
   

It might take a while to finish installation. Once it’s done, you can verify that Python is set up correctly.

Step 4: Verify Your Installation

Test that the python3.8 --version command returns the latest version:

$ python3.8 --version
Python 3.8.4

If you see Python 3.8.4, then you’re all set!

If you have some extra time on your hands, you can also run the test suite to make sure everything is working properly on your system.

To run the test suite, type the following command:

$ python3.8 -m test

You’ll probably want to find something else to do for a while, as your computer will be running tests for some time. If all the tests pass, then you can be confident that your brand-new Python build is working as expected!