Python Installation

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6 minute read

Gregor von Laszewski (laszewski@gmail.com)

Learning Objectives

  • Learn how to install Python.
  • Find additional information about Python.
  • Make sure your Computer supports Python.

In this section, we explain how to install python 3.8 on a computer. Likely much of the code will work with earlier versions, but we do the development in Python on the newest version of Python available at https://www.python.org/downloads .

Hardware

Python does not require any special hardware. We have installed Python not only on PC’s and Laptops but also on Raspberry PI’s and Lego Mindstorms.

However, there are some things to consider. If you use many programs on your desktop and run them all at the same time, you will find that in up-to-date operating systems, you will find yourself quickly out of memory. This is especially true if you use editors such as PyCharm, which we highly recommend. Furthermore, as you likely have lots of disk access, make sure to use a fast HDD or better an SSD.

A typical modern developer PC or Laptop has 16GB RAM and an SSD. You can certainly do Python on a $35-$55 Raspberry PI, but you probably will not be able to run PyCharm. There are many alternative editors with less memory footprint available.

Python 3.9

Here we discuss how to install Python 3.9 or newer on your operating system. It is typically advantageous to use a newer version of python so you can leverage the latest features. Please be aware that many operating systems come with older versions that may or may not work for you. YOu always can start with the version that is installed and if you run into issues update later.

Python 3.9 on macOS

You want a number of useful tools on your macOS. This includes git, make, and a c compiler. All this can be installed with Xcode which is available from

Once you have installed it, you need to install macOS XCode command-line tools:

$ xcode-select --install

The easiest installation of Python is to use the installation from https://www.python.org/downloads. Please, visit the page and follow the instructions to install the python .pkg file. After this install, you have python3 available from the command line.

Python 3.9 on macOS via Homebrew

Homebrew may not provide you with the newest version, so we recommend using the install from python.org if you can.

An alternative installation is provided from Homebrew. To use this install method, you need to install Homebrew first. Start the process by installing Python 3 using homebrew. Install homebrew using the instruction in their web page:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Then you should be able to install Python using:

$ brew install python

Python 3.9 on Ubuntu 20.04

The default version of Python on Ubuntu 20.04 is 3.8. However, you can benefit from newer version while either installing them through python.org or adding them as follows:

$ sudo apt-get update
$ sudo apt install software-properties-common
$ sudo add-apt-repository ppa:deadsnakes/ppa -y
$ sudo apt-get install python3.9 python3-dev -y

Now you can verify the version with

$ python3.9 --version

which should be 3.9.5 or newer.

Now we will create a new virtual environment:

$ python3.9 -m venv --without-pip ~/ENV3

Now you must edit the ~/.bashrc file and add the following line at the end:

alias ENV3="source ~/ENV3/bin/activate"
ENV3

Now activate the virtual environment using:

$ source ~/.bashrc

You can install the pip for the virtual environment with the commands:

$ curl "https://bootstrap.pypa.io/get-pip.py" -o "get-pip.py"
$ python get-pip.py
$ rm get-pip.py
$ pip install -U pip

Prerequisite Windows 10

Python 3.9.5 can be installed on Windows 10 using: https://www.python.org/downloads

Let us assume you choose the Web-based installer than you click on the file in the edge browser (make sure the account you use has administrative privileges). Follow the instructions that the installer gives. Important is that you select at one point [x] Add to Path. There will be an empty checkmark about this that you will click on.

Once it is installed chose a terminal and execute

python --version

However, if you have installed conda for some reason, you need to read up on how to install 3.9.5 Python in conda or identify how to run conda and python.org at the same time. We often see others are giving the wrong installation instructions. Please also be aware that when you uninstall conda it is not sufficient t just delete it. You will have t make sure that you usnet the system variables automatically set at install time. THi includes. modifications on Linux and or Mac in .zprofile, .bashrc and .bash_profile. In windows, PATH and other environment variables may have been modified.

Python in the Linux Subsystem

An alternative is to use Python from within the Linux Subsystem. But that has some limitations, and you will need to explore how to access the file system in the subsystem to have a smooth integration between your Windows host so you can, for example, use PyCharm.

To activate the Linux Subsystem, please follow the instructions at

A suitable distribution would be

However, as it may use an older version of Python, you may want to update it as previously discussed

Using venv

This step is needed if you have not yet already installed a venv for Python to make sure you are not interfering with your system python. Not using a venv could have catastrophic consequences and the destruction of your operating system tools if they really on Python. The use of venv is simple. For our purposes we assume that you use the directory:

~/ENV3

Follow these steps first:

First cd to your home directory. Then execute

$ python3 -m venv  ~/ENV3
$ source ~/ENV3/bin/activate

You can add at the end of your .bashrc (ubuntu) or .bash_profile or .zprofile` (macOS) file the line

If you like to activate it when you start a new terminal, please add this line to your .bashrc or .bash_profile or .zprofile` file.

$ source ~/ENV3/bin/activate

so the environment is always loaded. Now you are ready to install Cloudmesh.

Check if you have the right version of Python installed with

$ python --version

To make sure you have an up to date version of pip issue the command

$ pip install pip -U

Install Python 3.9 via Anaconda

We are not recommending ether to use conda or anaconda. If you do so, it is your responsibility to update the information in this section in regards to it.

:o2: We will check your python installation, and if you use conda and anaconda you need to work on completing this section.

Download conda installer

Miniconda is recommended here. Download an installer for Windows, macOS, and Linux from this page: https://docs.conda.io/en/latest/miniconda.html

Install conda

Follow instructions to install conda for your operating systems:

Install Python via conda

To install Python 3.9.5 in a virtual environment with conda please use

$ cd ~
$ conda create -n ENV3 python=3.9.5
$ conda activate ENV3
$ conda install -c anaconda pip
$ conda deactivate ENV3

It is very important to make sure you have a newer version of pip installed. After you installed and created the ENV3 you need to activate it. This can be done with

$ conda activate ENV3

If you like to activate it when you start a new terminal, please add this line to your .bashrc or .bash_profile

If you use zsh please add it to .zprofile instead.

Version test

Regardless of which version you install, you must do a version test to make sure you have the correct python and pip versions:

$ python --version
$ pip --version

If you installed everything correctly you should see

Python 3.9.5
pip 21.1.2

or newer.

Last modified June 20, 2021 : spelling (d59b3b2d)