pip is a standard package manager used to install & maintain packages for Python. The Python standard library comes with a collection of built-in functions & built-in packages.
Data science packages like scikit-learn & statsmodel are NOT part of the Python standard library. They can be installed through
pip, the standard package manager for Python, via the command line.
Pip has a variety of commands & option flags designed to manage Python packages.
We can print the
pip version the same way we print the Python version. It is important that the
pip version is compatible with the Python version. Here we see that
pip 19.1.1 is compatible with Python 3.5.2.
pip is giving us an upgrade warning, we can upgrade using pip itself:
pip using itself:
Viewing a Pip List
Before we make any installs, it is a good idea to see what is already installed. We can use
pip listin the command line, & it will display the Python packages in our current working environment in alphabetical order.
In the following example, we will learn how we can install the
scikit-learn package, which will install the other necessary dependencies.
We may notice from the logs that more then the
scikit-learn package is being installed. This is because
pip will install any other packages that
scikit-learn depends on. These other packages are called dependencies.
Installing a Specific Package Version
pip will always install the latest version, so if we wish to install an older version of
scikit-learn, all we need to do is specify it in the installation statement use a double equal sign:
If the package we are looking to use is already installed but simply out of date, we can update the package in a similar way we upgraded
This upgrade will also upgrade any necessary dependency packages as well, automatically.
Installing & Upgrading the
pip install more than one Python package, the packages can be listed in line with the same
pip install command as long as they are separated with spaces. Here we are installing both
scikit-learn & the
statsmodel package in one line of code.
We can also upgrade multiple packages in one line of code.
Installing Packages With
If we want to install many packages at once, we can save them one package per line in a text file called
requirements.txt. If we preview the file, it looks like this:
It’s conventional for Python package developers to create a
requirements.txt file in their Github repositories listing all dependencies for
pip to find & install.
-r option flag in
pip install to install packages from the file specified after the option flag. Keep in mind that naming this file
requirements.txt is conventional but not required.
Using our examples,
pip install -r requirements.txt will have the same effect as
pip install scikit-learn statsmodel. Typing out each package could get messy if you needed to install ten packages. Using the
requirements.txt file is much cleaner.
is the same as
Installing Packages - Python Packaging User Guide
This section covers the basics of how to install Python . It's important to note that the term "package" in this…