Installing Packages¶. This section covers the basics of how to install Python packages. It’s important to note that the term “package” in this context is being used to describe a bundle of software to be installed (i.e. As a synonym for a distribution).
- Config file content. To specify a keyring backend, set the default-keyring option to the full path of the class for that backend, such as keyring.backends.OSX.Keyring. If keyring-path is indicated, keyring will add that path to the Python module search path before loading the backend.
- Prerequisites for installing Python3 on Mac Install Xcode. Xcode is Apple's Integrated Development Environment (IDE). You might already have Xcode on your Mac.
Contents
Lesson Goals
This lesson shows you how to download and install Python modules. Thereare many ways to install external modules, but for the purposes of thislesson, we’re going to use a program called pip, easily installable on mac/linux and windows. As of Python 2.7.9 and newer, pip is installed by default. This tutorial will be helpful for anyone using older versions of Python (which are still quite common).
Introducing Modules
One of the great things about using Python is the number of fantasticcode libraries that are widely and easily available that can save you alot of coding, or simply make a particular task (like creating a CSVfile, or scraping a webpage) much easier. When Googling for solutions toproblems, you’ll often find sample code that uses code libraries youhaven’t heard about before. Don’t let these scare you away! Once theselibraries are installed on your computer, you can use them by importingthem at the beginning of your code; you can import as many libraries asyou’d like, such as
For new Python users, it can be a bit intimidating to download andinstall external modules for the first time. There are many ways ofdoing it (thus adding to the confusion); this lesson introduces one ofthe easiest and most common ways of installing python modules.
The goal here is to install software on your computer that canautomatically download and install Python modules for us. We’re going touse a program called pip.
Note: As of Python 3.4, pip will be included in the regular install.There are many reasons why you might not have this version yet, and incase you don’t, these instructions should help.
Mac and Linux instructions
As per the pip documentation, we can download a python script to installpip for us. Using a Mac or Linux, we can install pip via the commandline by using the curl command, which downloads the pip installationperl script.
once you’ve downloaded the get-pip.py file, you need to execute it withthe python interpreter. However, if you try to execute the script withpython like
the script will most likely fail because it won’t have permissions toupdate certain directories on your filesystem that are by default set sothat random scripts cannot change important files and give you viruses.In this case—and in all cases where you need to allow a script that youtrust to write to your system folders—you can use the sudo command(short for “Super User DO”) in front of the python command, like
Windows Instructions
As with the above platforms, the easiest way to install pip is throughthe use of a python program called get-pip.py, which you can downloadhere. When you open this link, you might be scared of the massivejumble of code that awaits you. Please don’t be. Simply use your browserto save this page under its default name, which is get-pip.py. It mightbe a good idea to save this file in your python directory, so you knowwhere to find it.
Once you have saved this file, you need to run it, which can be done intwo ways. If you prefer using your python interpreter, just right-clickon the file get-pip.py and choose “open with” and then choose whateverpython interpreter you care to use.
If you prefer to install pip using the windows command line, navigate towhatever directory you’ve placed python and get-pip.py. For thisexample, we’ll assume this directory is python27, so we’ll use thecommand C:>cd python27. Once you are in this directory, to install pip run thecommand Fantamorph software, free download.
If you want more information or help with a weird error message, check out the StackOverflowpage that seems to be regularly updated.
Installing Python Modules
Now that you have pip, it is easy to install python modules since itdoes all the work for you. When you find a module that you want to use,usually the documentation or installation instructions will include thenecessary pip command, such as
Remember, for the same reasons explained above (on Mac or Linux systems, but not Windows), you might need to run pip with sudo, like
Sometimes, especially on Windows, you may find it helpful to use the -m flag (to help python find the pip module), like
Happy installing!
This guide discusses how to install packages using pip anda virtual environment manager: either venv for Python 3 or virtualenvfor Python 2. These are the lowest-level tools for managing Pythonpackages and are recommended if higher-level tools do not suit your needs.
Note
This doc uses the term package to refer to aDistribution Package which is different from an ImportPackage that which is used to import modules in your Python source code.
Installing pip¶
pip is the reference Python package manager. It’s used to install andupdate packages. You’ll need to make sure you have the latest version of pipinstalled.
Windows¶
The Python installers for Windows include pip. You should be able to accesspip using:
Will minecraft windows 10 work on mac. You can make sure that pip is up-to-date by running:
Linux and macOS¶
Debian and most other distributions include a python-pip package, if youwant to use the Linux distribution-provided versions of pip seeInstalling pip/setuptools/wheel with Linux Package Managers.
You can also install pip yourself to ensure you have the latest version. It’srecommended to use the system pip to bootstrap a user installation of pip:
Afterwards, you should have the newest pip installed in your user site:
Installing virtualenv¶
Note
If you are using Python 3.3 or newer, the venv module isthe preferred way to create and manage virtual environments.venv is included in the Python standard library and requires no additional installation.If you are using venv, you may skip this section.
virtualenv is used to manage Python packages for different projects.Using virtualenv allows you to avoid installing Python packages globallywhich could break system tools or other projects. You can install virtualenvusing pip.
On macOS and Linux:
On Windows:
Creating a virtual environment¶
venv (for Python 3) and virtualenv (for Python 2) allowyou to manage separate package installations fordifferent projects. They essentially allow you to create a “virtual” isolatedPython installation and install packages into that virtual installation. Whenyou switch projects, you can simply create a new virtual environment and nothave to worry about breaking the packages installed in the other environments.It is always recommended to use a virtual environment while developing Pythonapplications.
To create a virtual environment, go to your project’s directory and runvenv. If you are using Python 2, replace venv with virtualenvin the below commands.
On macOS and Linux:
On Windows:
The second argument is the location to create the virtual environment. Generally, youcan just create this in your project and call it env.
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venv will create a virtual Python installation in the env folder.
Note
You should exclude your virtual environment directory from your versioncontrol system using .gitignore or similar.
Activating a virtual environment¶
Before you can start installing or using packages in your virtual environment you’llneed to activate it. Activating a virtual environment will put thevirtual environment-specificpython and pip executables into your shell’s PATH.
On macOS and Linux:
On Windows:
You can confirm you’re in the virtual environment by checking the location of yourPython interpreter, it should point to the env directory.
On macOS and Linux:
On Windows:
As long as your virtual environment is activated pip will install packages into thatspecific environment and you’ll be able to import and use packages in yourPython application.
Leaving the virtual environment¶
If you want to switch projects or otherwise leave your virtual environment, simply run:
If you want to re-enter the virtual environment just follow the same instructions aboveabout activating a virtual environment. There’s no need to re-create the virtual environment.
Installing packages¶
Now that you’re in your virtual environment you can install packages. Let’s install theRequests library from the Python Package Index (PyPI):
pip should download requests and all of its dependencies and install them:
Installing specific versions¶
pip allows you to specify which version of a package to install usingversion specifiers. For example, to installa specific version of requests:
To install the latest 2.x release of requests:
To install pre-release versions of packages, use the --pre flag:
Installing extras¶
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Some packages have optional extras. You can tell pip to install these byspecifying the extra in brackets:
Installing from source¶
pip can install a package directly from source, for example:
Additionally, pip can install packages from source in development mode,meaning that changes to the source directory will immediately affect theinstalled package without needing to re-install:
Installing from version control systems¶
pip can install packages directly from their version control system. Forexample, you can install directly from a git repository:
For more information on supported version control systems and syntax, see pip’sdocumentation on VCS Support.
Installing from local archives¶
If you have a local copy of a Distribution Package’s archive (a zip,wheel, or tar file) you can install it directly with pip:
If you have a directory containing archives of multiple packages, you can tellpip to look for packages there and not to use thePython Package Index (PyPI) at all:
This is useful if you are installing packages on a system with limitedconnectivity or if you want to strictly control the origin of distributionpackages. Mac sierra d manual display error download.
Using other package indexes¶
If you want to download packages from a different index than thePython Package Index (PyPI), you can use the --index-url flag:
If you want to allow packages from both the Python Package Index (PyPI)and a separate index, you can use the --extra-index-url flag instead:
Upgrading packages¶
pip can upgrade packages in-place using the --upgrade flag. For example, toinstall the latest version of requests and all of its dependencies:
Using requirements files¶
Instead of installing packages individually, pip allows you to declare alldependencies in a Requirements File. Forexample you could create a requirements.txt file containing:
And tell pip to install all of the packages in this file using the -r flag:
Freezing dependencies¶
Pip can export a list of all installed packages and their versions using thefreeze command:
Which will output a list of package specifiers such as:
This is useful for creating Requirements Files that can re-createthe exact versions of all packages installed in an environment.