Installing packages

Hey there! Welcome back to the Python basics tutorial. Last time you learned about libraries and modules. Today you'll discover how to install them easily.

There's a tool called pip (Pip install packages) which is the most common way of installing third-party packages from PyPI (Python Packaging Index).

Installation

Windows

Pip is installed by default with Python on Windows. To verify, run pip --version in the Command Prompt.

MacOS

Pip is also installed by default with Python by both Homebrew and the installer on python.org.

Linux

On Linux, pip is usually not installed. Don't get worried, you can install it easily.

Ubuntu/Debian

sudo apt-get install python3-pip

Fedora

Pip is installed by default when you install the python3 package.

Arch Linux

pacman -s python-pip

Running Pip

Fire up your terminal emulator : Command Prompt or cmd on Windows, Terminal on Mac and Linux.

Remember, run the following commands from a terminal emulator, NOT from a Python console.

Now type in pip --version or pip3 --version in MacOS/Linux to verify pip installation. Now, we can install a popular library called numpy which is used for mathematical stuff. To install packages with pip:

pip install <package_name>

So, to install numpy we will do:

pip install numpy

If you run the command in your terminal, you'll see something like this:

$ pip install numpy
Collecting numpy
  Using cached https://files.pythonhosted.org/packages/ff/7f/9d804d2348471c67a7d8b5f84f9bc59fd1cefa148986f2b74552f8573555/numpy-1.15.4-cp36-cp36m-manylinux1_x86_64.whl
Installing collected packages: numpy
Successfully installed numpy-1.15.4

You may see a progress bar too.

That's all to installing packages. You can simply open up a Python file now and import numpy and use it.

There's also another tool named easy_install but we'll be using Pip in these tutorials.

Troubleshooting

If you get an error 'Pip' is not recognized as a command. or something similar, you can follow the steps below, or skip to the last section "get-pip.py".

Windows

Reinstall Python

If you did not check the box Add Python to PATH box during installation, you can reinstall Python again and make sure to check the box this time.

Add Python to PATH

To configure your current installation:

Open the Python console and type in these commands:

>>> import os
>>> import sys
>>> os.path.dirname(sys.executable)

This will return a location or a path. Copy this.

Now go to System Properties -> Advanced, or just press Windows Key + Pause. Then click "Environment Variables". Create a new "System Variable" called PYTHON_HOME and set the value to the path you just copied. Then find another "System Variable" called PATH, click Edit, and add this to the end: ;%PYTHON_HOME%\;%PYTHON_HOME%\Scripts\. and save. Now open up a new command prompt and type in pip --version again. It should work now.

MacOS/Linux

First of all, check if you're actually running pip3 or pip . If it's pip, try again with pip3. If none of them work:

Try sudo easy_install pip, or try brew install python3 again on MacOS. On Linux, try sudo apt-get install python3-pip.

get-pip.py

If none of the solutions above work, you can try using get-pip.py. Download it from https://bootstrap.pypa.io/get-pip.py , open up the terminal/Command Prompt, navigate to the file and do python get-pip.py on Windows and python3 get-pip.py on MacOS/Linux. This should fix it. If not, Google is your friend!