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Python Installation Tutorial

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The first hurdle to jump over in regards to coding in Python is setting up your environment. The operating system (OS) I'm coding in at the time of publication is Ubuntu 18.04, so if you don't have this then you're effectively out of luck :-). In all seriousness, the three major players in operating systems are Linux, OS X, and Windows. I'll provide installation instructions for all three along with recommended text editors. I'll also provide insights on how to run your first Python program and how to use pip which is a popular package manager system.

Installing Python on Linux (Ubuntu 18.04)

To see if Python is installed on your machine open up the terminal and type in the following:

python

You can fire-up the terminal by using the keyboard shortcut: ctr + alt + t. The terminal in Ubuntu 18.04 looks like the following:

Figure 1.0. Install Python on Linux

Figure 1.0: Install Python on Linux.

The output should look something like the following:

Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56) 
[GCC 7.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

Look at this line of output:

Python 3.6.5 |Anaconda, Inc.| (default, Apr 29 2018, 16:14:56)

If you got something like this then woot-woot, Python 3.6.5 is installed on your machine. If Python 2.7 or later is installed then it's OK, you don't need to uninstall it, you just need to get Python3 running. Luckily this process is super easy with Ubuntu:

The word sudo is abbreviation for "super user do" and it allows programs to be executed as a super user, aka the root user. The apt command means Advanced Package Tool, which is a package manager for Debian based operating systems like Ubuntu. The apt-get command is the APT package handling utility. You can see a list of the commands that's available for it by typing apt-get into the terminal.

Install Python on OS X

Like Linux, Python is already installed on a variety of OS X systems. You can confirm that Python is installed by going to: Applications → Utilities → Terminal. Next, type the following into the terminal:

python -V

The command will output the version of Python which is:

Python 2.7.3

Any version between 2.7.0 and 2.7.10 is common. The next step is to test if you have Python3 on your computer. You can do this by typing the following into the terminal:

python3

If the output shows that Python 3 is installed then you're safe... for now. If you get an error then that's not cool and you have some work to do. You can fix this by downloading and installing Python with the appropriate Mac OS X installer that matches your system.

Install Python on Windows

It's a high probability that if you're running a Windows operating system then Python won't be there by default. To discover if Python is installed on your machine you can open the terminal and then type python. If it's installed then that command will run python.exe and reveal the version number. If you get a rude message like the following:

'python' is not recognized as an internal or external command, operable program or batch file

This tells you that Python is not installed and you have to set it up. Follow the steps below to install and setup Python on your computer.

Step one: Download the latest version of Python on your machine:

Step two: Open and start the Windows installer that matches your system. If you click "Install Now" then Python is installed in the "user" directory, but if you change its location then make a note of where it's installed.

Step three: You'll have an option to add Python to PATH. In layman terms, the PATH is where the computer searches for Python when you type it via command prompt. If you check this box then Python will be available via this option, if not then when you type python in the console an error will occur. Therefore, it's a good idea to check this option so that you can type in python commands via command prompt. If you installed Python without selecting this option then no biggie as you have to manually add the path to your system. Here are the steps on how to add Python to the PATH:

If you don't know the location of python.exe then don't panic, just search for python.exe in the Windows menu. Once located, right click the file, select properties, and view the Location. Right click to copy the full path and then paste it at the end of the Path user variable. If you don't have a Path user variable then click the new button, add a variable named Path, and then add the value which is the location or "path" of the python.exe file. Once done type "python" into the terminal to ensure that everything was set up properly and that it runs.

Hello Peeps!

Once Python is installed we can test a simple Hello Peeps program to whet our appetite with the language. Open up a text editor on your operating system – anything bare bones would do like Notepad on Windows, TextEdit for OS X, or Gedit in Ubuntu. Open up a blank text file and add the following snippet:

print("Hello peeps!")

Go ahead and save the file as HelloPeeps.py to a location of your choice. It can be anywhere, just don't forget where you put it... pinky swear? 👍The next step is to fire up the terminal or command prompt (if using Windows) and then change into the directory where HelloPeeps.py is located. To change directories use the cd command. So, if HelloPeeps.py is in a Programs folder on your Desktop in Ubuntu then it should look something like this:

cd Desktop/Programs

Once you’re in the directory where your Python file is located the next step is to run the program by using the following command:

python HelloWorld.py

Python is called an interpreted language because the programs can be run directly. The file is still compiled; it's just done internally or behind the scenes and is an implementation detail of the language. This is different from Java which if run through the terminal must be explicitly compiled first, and then the byte code is interpreted by the Java Virtual Machine.

You can also run Python code directly through the shell so that it doesn't have to be added to a file and then run – this is convenient when you want quick feedback and feeling too lazy to type code into a text editor. This is officially known as the Python Shell and is what we'll be using to learn the fundamental concepts about Python. You can access the Python Shell by opening up the terminal and typing python3. If successful the following will appear:

The Python Shell

Figure 1.1: The Python Shell.

If all is good then simply type the following into the terminal:

>>> print("Hello World!")

The output will be:

Hello World!

How to install packages with Pip

Once you got Python installed and tested on your machine then great, you're one step closer to coding in Python. However, this is not the end to all of your installation drama, in matter of fact it's more like the beginning. In the course of your Python learning experience there will be plenty of resources that you'll need to install that's not included with Python by default.

This can be kind of annoying, but the good thing is there's software that helps you install other software. What you'll need is the help of a package manager, and one popular tool for this is pip. Depending on what flavor of Python you're running pip should be preinstalled. More specifically, it comes preinstalled on Python 2.7.9 and later, and Python 3.4 and later (pip3).

If you're using an older version of Python I would highly recommend against that as the code crafted in this book is for Python version 3.6+. However, if you insist of using an older version of Python you can follow these two simple steps to installing pip:

  1. Download get-pip.py. Or, you can use curl to download pip by using the following command:
    curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

  2. Run get-pip.py. You can do this by using the following command: python get-pip.py

That's it! Below are the steps on how you can install pip on OS X and various Linux environments.

OS X

sudo easy_install pip

Debian/Linux

apt install python3-pip

Fedora

dnf install python3

CentOS

yum install python-pip

Pip is a command line tool, so to install a package for example you just type a command into the terminal. Here's a quick rundown of some of the key functionality of pip. To install a package use the follow command:

$ pip install SomePackage

To uninstall a package use the following command:

$ pip uninstall SomePackage

To upgrade a package do:

$ pip install –upgrade SomePackage

To see a list of packages that's outdated use the following command:

$ pip list –outdated