How to Install Python on Your System: A Guide

Checking the Python Version on Windows

To check whether you already have Python on your Windows machine, open a command-line application like PowerShell or the Windows Terminal.

Follow the steps below to open PowerShell on Windows:

1. Press the Win key.
2. Type PowerShell.
3. Press Enter.

Alternatively, you can right-click the Start button and select Windows PowerShell or Windows PowerShell (Admin). In some versions of Windows, you’ll find Terminal or Terminal (admin).

With the command line open, type in the following command and press the Enter key:

PS> python --version
Python 3.x.z

Using the --version switch will show you the installed version. Note that the 3.x.z part is a placeholder here. In your machine, x and z will be numbers corresponding to the specific version you have installed.

Alternatively, you can use the -V switch:

PS> python -V
Python 3.x.z

Using the python -V or python—-version command, you can check whether Python is installed on your system and learn what version you have. If Python isn’t installed on your OS, you’ll get an error message.

Knowing the Python Installation Options on Windows

You’ll have different options to install Python if you’re on a Windows machine. Here are three popular ones:

1. The official Python installer for Windows: This approach involves downloading the Python installer directly from the Python.org website. It’s recommended for intermediate and advanced developers who need more control during the setup process.
2. The Microsoft Store: The quickest installation option on Windows involves using the Microsoft Store app. This is recommended for beginner Python programmers looking for an easy-to-set-up interactive experience.
3. The Windows subsystem for Linux (WSL): The WSL allows you to run a Linux environment directly on Windows.

In this section, you’ll focus on only the first two options, which are the most popular ones on Windows environments.

If you want to install Python in the WSL, you can read the Linux-related sections of this tutorial after installing the Linux distribution of your choice.

Step 1: Download the Official Python Installer

Follow the steps below to download the official Python installer from the Python.org site:

1. Open your browser and navigate to the downloads page for Windows on Python.org.
2. Under the Python Releases for Windows heading, click the link for the Latest Python 3 Release - Python 3.x.z.
3. Scroll to the bottom and select either Windows installer (64-bit) or Windows installer (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 you finish downloading the installer, then you can move on to the next step.

Step 2: Run the Python Installer

Once you’ve chosen and downloaded an installer, run it by double-clicking on the file. An installation wizard like the one below will appear on your screen:

There are four important 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 allows you to customize the installation location and some additional features, including installing pip and IDLE.
3. The Use admin privileges when installing py.exe allows every user on the machine access the py.exe launcher.
4. The Add python.exe to PATH checkbox is also 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.

As you can conclude, the official Python installer gives you granular control over the installation process on Windows.

Use the options in the dialog box to customize the installation to meet your needs. Then click Install. That’s it! You now have the latest version of Python 3 on your Windows machine!

If you’re interested in where the installation is located, then you can use the where.exe command in PowerShell:

PS> where.exe python
C:\Users\realpython\AppData\Local\Microsoft\WindowsApps\python.exe

Note that the where.exe command will work only if Python has been installed for your user account.

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

Open the Microsoft Store app on your Windows machine and search for Python. You’ll likely see multiple versions that you can choose to install. Select the latest version of Python available in the store to open the installation page.

Once on the Python application’s page, you’re ready to install Python on your system, which is the second step.

Step 2: Install the Python App

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

1. Click the Get button.
2. Wait for the app to download and install.

Once the installation is complete, open Windows PowerShell and run the python --version command to confirm that Python is installed on your machine.

Along with the Python interpreter, you can access a few other tools, including pip and IDLE!

Checking the Python Version on a macOS

To check which Python version you have on your Mac, open a command-line application like Terminal.

Here’s how you open Terminal on macOS:

1. Press the Cmd+Space keys.
2. Type Terminal.
3. Press Enter.

Alternatively, you can open Finder and navigate to Go → Utilities → Terminal.

With the command line open, type in the following commands:

$ python3 --version

This command should respond with a version number. Alternatively, you can use the shorter -V switch, which has the same effect.

In practice, you’d want to get the latest version of Python if none of the above commands returns a version number or if you have a version of Python 3 that isn’t the latest available. Now, you can read through the following sections to learn about the different options for installing Python on macOS.

Knowing the Python Installation Options on macOS

You’ll have two main options to install Python on macOS:

1. The official Python installer for macOS: This option involves downloading the official installer from the Python.org website and running it on your machine.
2. The Homebrew package manager: This option involves downloading and installing the Homebrew package manager if you don’t already have it and then running the required installation command in your terminal application.

The official Python installer and the Homebrew Python distribution will work, but the Python Software Foundation maintains only the official installer.

Now that you know your option for installing Python on macOS, it’s time to get your hands dirty and go through the installation process.

Step 1: Download the Python Official Installer

You can install Python in two steps using the official installer:

1. Open a browser window and navigate to the downloads page for macOS.
2. Under the Python Releases for macOS heading, click the link for the Latest Python 3 Release - Python 3.x.z.
3. Scroll to the bottom and click macOS 64-bit universal2 installer to start the download.

When the download is finished, move on to the next step.

Step 2: Run the Python Installer

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

Follow these on-screen steps to complete the installation:

1. Press Continue a couple of times until you’re asked to agree to the software license agreement. Then click Agree.
2. Select the install destination. You most likely won’t need 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 ensure your SSL root certificates are updated.

You now have the latest version of Python on your macOS computer, and you’re ready to start coding cool apps!

Step 1: Install the Homebrew Package Manager

If you already have Homebrew installed on your macOS system, then you can skip this step. If you don’t have it installed, then use the following procedure:

1. Open a browser and navigate to http://brew.sh/.
2. Copy the installation command under the Install Homebrew heading.
3. Open a terminal window and paste the command, then press Enter.
4. Enter your macOS user password when prompted.

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

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

Step 2: Install Python With Homebrew

Installing Python with the Homebrew package manager is now as straightforward as running the following command:

$ brew install python

This command will download, install, 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. If you get an error message, then go through the install steps again to make sure you have a working installation.

Checking the Python Version on Linux

Most Linux distributions come with Python installed by default. In most cases, the installed version won’t be the latest Python. To find out which version of Python you have on Linux, open a terminal window and run the following command:

$ python3 --version

If you have Python on your machine, then this command will respond with a version number. Instead of --version, you can use the shorter -V switch:

$ python3 -V

Either of these switches will give you the version number of the Python installation that the command is associated with. If your current version is outdated, you’ll want to get the latest version of Python.

Knowing the Python Installation Options on Linux

There are two main ways to install the official Python distribution on a Linux operating system:

1. Install from a package manager: This is the most common installation option on most Linux distributions. It involves running a command from the command line.
2. Build from source code: This option can be difficult because it involves running a series of commands from the command line as well as making sure you have the correct dependencies installed to build Python from its source code.

Not every Linux distribution has Python in their package repository. So, depending on your distribution, building Python from source code might be your only option.

If your Linux distribution includes Python in its list of available packages, you may realize that the version in the repository isn’t the latest version available on Python.org. In this situation, your only option to have the latest version is to build it from the source.

If you have a rolling release Linux distribution like Arch, Manjaro, openSUSE Tumbleweed, and others, then you’ll probably have the latest version of Python available for installation or update using the system’s package manager. In this situation, to update your Python, you’d only have to update the system with the appropriate commands.

The installation option boils down to whether your Linux has Python available in its software repository and whether you need to control the details of the installation.

Step 1: Download the Python Source Code

To start, you need to clone the cpython repository from GitHub or get the Python source code from Python.org. If you go to the downloads page, then you’ll find the latest source for Python 3 at the top.

When you select the latest Python 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 to use your command line, then you can use wget to download the file to your current directory:

$ wget https://www.python.org/ftp/python/3.x.z/Python-3.x.z.tgz

For this command to work, you must specify the version to download. 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 for Building Python

There are a few distro-specific steps involved in building Python from source. The goal of this section is to prepare your system for building Python. Below, you’ll find specific steps for some popular Linux distributions.

$ sudo apt update
$ sudo apt upgrade

$ sudo apt 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

$ sudo zypper install -t pattern devel_C_C

$ sudo yum -y update

$ sudo yum -y groupinstall "Development Tools"
$ sudo yum -y install gcc openssl-devel bzip2-devel libffi-devel

Step 3: Build and Install Python on Your System

Once you have your system ready and the TAR file with the Python source code, you can unpack the source into a directory:

$ tar xvf Python-3.x.z.tgz
$ cd Python-3.x.z/

This command unpacks the source code into a directory named after the TAR file. Note that the TAR file will show a specific Python version rather than 3.x.z in your output.

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

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

The enable-optimizations flag will enable some optimizations within Python to make it run 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.

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

$ make -j 8

Finally, you have to install your compiled version of Python. You’ll use the altinstall target here to avoid overwriting the system Python. You’ll need to run the following command as root:

$ sudo make altinstall

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

Step 4: Verify Your Python Installation

Test that the command below returns the compiled version of Python:

$ python3.x --version
Python 3.x.z

Again, in your case, this command would need to be run using the specific version number.

You can also run the Python test suite to ensure everything works properly on your system. To do this, execute the following command:

$ python3.x -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 will work as expected!