How to Install Python3 on Ubuntu [3 Best Methods]

Written by

Ojash

Reviewed by

Akshat

Last updated: June 6, 2024

Expert verified

Setting up Python 3 on Ubuntu might feel overwhelming, especially if you’re new to Linux, but don’t worry—I’ve got you covered. This guide will walk you through how to install python3 in Ubuntu. You’ll learn how to set up environment variables, write your first Python script, and create virtual environments for your projects. By the end, you’ll have a solid foundation to start coding in Python on your Ubuntu machine. Let’s explore and get Python up and running smoothly so you can focus on creating amazing projects.

How to Install Python3 on Ubuntu

Here are the detailed steps to install python3 on Ubuntu using three different methods:

1. Installing Python Using Apt Package

1. Open the Terminal by pressing Ctrl + Alt + T.

2. Run the following command to update the package:

sudo apt update

3. This command will update the package lists for upgrades and new package installations.

4. After the update process completes, run the following command to upgrade:

sudo apt upgrade

5. The command will upgrade the installed packages.

6. Ubuntu provides Python 3 through its official repository. For installation, open the Terminal and execute the following command to install python Linux:

sudo apt install python3

7. After the execution of the command, Python 3 will be installed along with the required dependencies.

8. To check Python 3 is correctly installed on your system, run the following command: 

python3 --version

9. If the installation was successful, the Terminal will display the Python version installed on your system.

2. Installing Python 3 Using deadsnakes PPA

The deadsnakes PPA is a popular and reliable Personal Package Archive (PPA) that provides newer versions of Python than those available in the official Ubuntu repositories. Using this PPA allows you to easily install and manage multiple Python versions on your system. This method is particularly useful when you need a specific version of Python for compatibility with certain projects or libraries.

1. To add the deadsnakes PPA to your system, use the following command: 

sudo add-apt-repository ppa:deadsnakes/ppa

Press Enter when prompted to add the PPA. This PPA is maintained by trusted developers and provides access to various Python versions.

2. After adding the PPA, update your package list:

sudo apt update

It will ensure your system is aware of the new packages available from the deadsnakes PPA.

3. Now, you can install the desired version of Python 3. 

sudo apt install python3.9

Replace 3.9 with the version you need.

4. Confirm the installation by checking the Python version. 

python3.9 --version

This ensures that Python 3.9 is correctly installed on your system.

3. Installing Python 3 from Source

Building Python from source gives you the flexibility to customize the installation and optimize performance for your specific system. This method is ideal for advanced users who need specific configurations or the latest version of Python that is not yet available in any repository.

1. Download the desired version of Python source code from the official Python website. 

wget https://www.python.org/ftp/python/3.9.0/Python-3.9.0.tgz

Replace the URL with the version you want to download.

2. Extract the downloaded tarball to prepare for the build process.

tar -xvf Python-3.9.0.tgz

3. Ensure you have the necessary build dependencies installed. 

sudo apt-get install build-essential zlib1g-dev

This step installs essential tools required for building Python.

4. Navigate to the extracted directory and configure the build environment. 

cd Python-3.9.0

5. Now run the command:

./configure --enable-optimizations

The –enable-optimizations flag optimizes the binary for better performance.

6. Compile the source code. 

make -j 2

The -j 2 flag uses 2 CPU cores for the build process. Adjust this number based on the number of cores available on your system.

7. After compilation, install Python using altinstall to avoid overwriting the default system Python.

sudo make altinstall

8. Verify the installation by checking the Python version.

python3.9 --version

How to Configure Python 3 on Ubuntu

Configuring Python 3 on Ubuntu is essential for ensuring optimal usage and leveraging its benefits. This section will cover two crucial aspects: setting up environment variables and installing Python packages and libraries. You can customize your Python environment and enhance its functionality by following the steps below.

1. Setting Up Environment Variables

To ensure Python functions properly on Ubuntu, you need to configure the environment variables. This allows for seamless execution and accessibility. Follow these steps to set up environment variables:

1. Open the Terminal.
2. Execute the following command to open the .bashrc file in a text editor:

nano ~/.bashrc

3. Scroll to the bottom of the file and add the following lines:

export PATH="/usr/local/bin:$PATH"
export PATH="/usr/local/sbin:$PATH"

4. It will set the environment variables for the proper functioning of python.

5. Save the changes by pressing Ctrl + O and exit the text editor by pressing Ctrl + X.

6. To apply the changes, run the following command:

source ~/.bashrc

2. Installing Python Packages and Libraries

Python packages and libraries expand the capabilities of the language. With these libraries, you can supercharge your Python projects and tap into a vast array of functionality. To install additional packages using pip, the package installer for Python, follow these steps:

1. Launch the Terminal window and run the following command to install pip:

sudo apt install python3-pip

2. Once pip is installed, you can use it to install Python packages.

3. To install the python packages, run the following command:

pip3 install package-name

Replace package-name with the actual package name.

Creating Your First Python Program

Writing your first Python program is an exciting step towards learning this versatile and powerful programming language. I will walk you through creating a simple Python script, running it, and understanding the basics of Python syntax.

1. Ensure that Python is installed on your system. Open your favorite text editor or Integrated Development Environment (IDE). 

2. Create a new file and name it hello.py. This file will contain your first Python program. In the hello.py file, write the following code:

print("Hello, World!")

This simple program uses the print function to display the message “Hello, World!” on the screen.

3. Save the hello.py file in your desired directory. Ensure you remember the directory path as you will need to navigate to it to run the script.

4. Open a terminal and navigate to the directory where you saved hello.py:

cd projects

5. Once you are in the correct directory, run the script using the Python interpreter:

python3 hello.py

6. You should see the output: Hello, World!

Creating a Virtual Environment for Python 3

Using virtual environments is a best practice in Python development. Virtual environments allow you to create isolated environments for different projects, ensuring that dependencies and packages do not conflict. This is particularly useful when working on multiple projects that require different versions of the same packages.

1. Before creating a virtual environment, you need to ensure the venv module is installed. This module is part of the Python standard library, but you may need to install it explicitly.

sudo apt install python3-venv

2. Create a new directory for your project and navigate to it. Then, create a virtual environment within this directory.

mkdir myproject

cd myproject

python3 -m venv myenv

This command creates a virtual environment named myenv in the myproject directory.

3. To start using the virtual environment, you need to activate it. This modifies your shell’s environment to use the virtual environment’s Python interpreter and packages.

source myenv/bin/activate

After activation, your shell prompt will change to indicate that you are now working within the virtual environment.

4. You can now install packages using pip within this isolated environment without affecting the global Python installation.

pip install package_name

5. Once you are done working in the virtual environment, you can deactivate it to return to your global Python environment.

deactivate

5 Common Errors When Installing Python 3

Installing Python 3 on Ubuntu is a straightforward but challenging process. By understanding these errors, you’ll be able to overcome issues and install Python 3 on Ubuntu. In this section, I will highlight five common errors that users may encounter during installation and provide guidance on resolving them.

1. 🐍 Command ‘python3’ Not Found

This error occurs when Python 3 is not installed correctly or the system path is not set up.

To resolve this, ensure you have installed Python 3 using sudo apt update and sudo apt install python3. Verify the installation with python3 --version. If the issue persists, check that /usr/bin/python3 is in your system’s PATH variable. Add it by editing your .bashrc file with nano ~/.bashrc, adding export PATH="/usr/bin:$PATH", and applying the changes with source ~/.bashrc.

2. 🔧 Dependency Issues During Installation

These issues arise when the system’s package list is outdated, or there are missing dependencies required for Python 3.

Before installing Python 3, update your package list and upgrade existing packages with sudo apt update and sudo apt upgrade to ensure all dependencies are met. If issues persist, use the deadsnakes PPA to get the latest Python versions and their dependencies by running sudo add-apt-repository ppa:deadsnakes/ppa, sudo apt update, and sudo apt install python3.x (replace x with the desired version number).

3. 🚫 Permission Denied While Installing Packages

This error occurs when attempting to install Python packages without sufficient permissions.

To fix this, use sudo to install packages system-wide, such as sudo apt install python3-pip and sudo pip3 install package-name. If you prefer to avoid using sudo, consider using a virtual environment to manage packages locally by creating one with python3 -m venv myenv, activating it with source myenv/bin/activate, and installing packages with pip install package-name.

4. 📉 Incorrect Python Version Installed

This issue arises when an older or wrong version of Python is installed, possibly due to default repository limitations.

Specify the desired version explicitly by using the deadsnakes PPA. For example, to install Python 3.9, run sudo add-apt-repository ppa:deadsnakes/ppa, sudo apt update, and sudo apt install python3.9. Verify the installed version with python3.9 --version to ensure you have the correct version.

5. ⚙️ Failure to Set Up Environment Variables

Issues with environment variables can prevent Python scripts from running correctly.

To resolve this, add Python paths to your environment variables by editing the .bashrc file with nano ~/.bashrc and adding export PATH="/usr/local/bin:$PATH" and export PATH="/usr/local/sbin:$PATH". Save and exit, then apply the changes with source ~/.bashrc. This ensures that Python and its packages are accessible from any terminal session, allowing for seamless execution and accessibility.

Ubuntu Python3 Install: Final Thoughts

In this guide, I’ve explored how to install python 3 on Linux using the APT package manager, the deadsnakes PPA, and building from source. I have also covered configuring Python, writing your first script, and creating virtual environments. These steps ensure you have a solid foundation in Python installation, configuration, and basic usage.

For further learning, I recommend exploring the following articles:

• Learn to check the version of the Python package to ensure compatibility and manage updates effectively.
• Explore how to fix the “python: command not found” error to ensure your Python installation is correctly set up and accessible.
• Discover how to fix the “You Have Held Broken Packages” error on Linux, which is crucial for resolving installation issues.

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