Installation Guide

Welcome to the first Python tutorial. We’re going to look at getting Python up and running on your computer, then look at a few simple operations to get to grips with the development environment and syntax.

Installation

Mac

Mac OSX ships with Python 2.7 which, while still a great language, is very outdated these days, so we need to upgrade:

  1. Make sure you’re running an updated version of OSX. You should at least have OS 10.3, and most modern Macs are running much later than that anyway, but it’s worth noting this requirement here.
  2. Head to the Python website.
  3. Click “Downloads”.
  4. There will be two options; one for Python 3 and one for Python 2. Download Python 3. At the time of writing, the version available is 3.5.2.
  5. When the download’s complete, your browser should automatically mount the disk image and open a Finder window of what’s inside, but if that doesn’t happen, you’ll have to find the file Python.mpkg in your downloads folder and double-click it to get started.
  6. Once the installer is running hit Continue a number of times and agree to the Free software license as well as enter your administrator password. Just follow the prompts and you’ll be fine.

If you get lost, have a look at this tutorial with pictures on DiveIntoPython3.

Windows:

  1. Head to the Python website.
  2. Click “Downloads”.
  3. There will be two options; one for Python 3 and one for Python 2. Download Python 3. At the time of writing, the version available is 3.5.2.
  4. Run the downloaded installer and click Next until you reach the Customization page.
  5. Scroll down to the bottom and choose to Add python.exe to PATH.
  6. Continue clicking Next until it’s installed.

If you get lost, have a look at this tutorial with pictures on DiveIntoPython3.

Linux

All modern Linux distributions should support installing Python 3 via the package manager. However, each distribution likes to do things slightly differently, so these instructions may need to be modified for your situation.

Debian/Ubuntu

Python 3 is available via apt, so you can install it with apt install python3.

Redhat/CentOS

Python 3 isn’t yet available in default Redhat/Centos installations, so you have to use the scl workaround:

  1. Install scl-utils: yum install scl-utils
  2. Install the extra repo needed for Pytyhon 3: rpm -Uvh https://www.softwarecollections.org/en/scls/rhscl/python33/epel-7-x86_64/download/rhscl-python33-epel-7-x86_64.noarch.rpm
  3. Install Python 3 with this new repo: yum install Python33 (no the second 3 is not a typo)
  4. Run scn enable python3 /bin/bash. This will put you into a shell that supports Python 3.

For more information on this process, take a look at this tutorial.

Arch

Python 3 is available via Pacman, so all you need to do is pacman -S python.

Gentoo

You’ve already got it :-)

Opening the REPL

Python is often developed with the aid of a REPL, or Read-Eval-Print-Loop. The REPL is a way of getting immediate feedback as you work. Python’s REPL is called IDLE.

It’s very important to find what Python version you are working with.

On Windows, open cmd or on Mac OS / GNU/Linux open terminal and type (without the $ sign):

$ python --version

What you should see is:

$ python 3.5.2

Any 3.* version should do for this tutorial to work.

Now, open the REPL by typing:

$ python

And you should see something like this:

Python 3.5.2 (default, Aug  6 2016, 15:44:26) 
[GCC 5.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 

Now you’re all set!