Install Python Packages Using pip

PyPi Statistics

You can check download statistics of Python Packages on PYPI at https://pypistats.org/. This is especially helpful if you want to choose from multiple packages.

Prefer pip

pip is preferred over OS tools (e.g., apt-get, yum, wajig, aptitude, etc.) for managing Python packages. If you are using Anaconda Python, use conda (instead of pip) to manage Python packages especially when you encounter dependency issues.

Install pip

On Ubuntu

apt-get install python3-pip

On Mac

pip should have already been installed when you instal Python using Homebrew or Anaconda.

Bootstrapping the pip Installer

The package ensurepip provides support for bootstrapping the pip installer into an existing Python installation or virtual environment.

sudo python3 -m ensurepip

Proper Way of Using pip

pip can be upgrade using the following command.
```
pip3 install --upgrade pip
```
However, you should avoid doing this (as it might causes issues) unless you have to upgrade and you are an experienced user. It is recommended that you upgrade pip via the system package management tools only.
Do NOT use sudo pip install pkg1 pkg2 install packages to system-wide locations. Instead, use pip install --user pkg1 pkg2 to install packages to your local directory.

https://github.com/pypa/pip/issues/5599

https://stackoverflow.com/questions/49940813/pip-no-module-named-internal

Install a Specific Version of a Python Package

List all available versions of a Python package.
```
pip3 install pylibmc==
```
Install a specific version of a Python package.
```
pip3 install MySQL_python==1.2.2
```
Install pyarrow with a verison of at least 0.14.0. Notice that you must quote pyarrow>=0.14.0 using single/double quotes.
```
pip3 install 'pyarrow>=0.14.0'
```
Install a Python package with a version in a range.
```
pip3 install "jupyterlab>=1.2.7,<2.0.0"
```
You can install the pre-release version of a package using the --pre option. For example, the current version of pybuilder (0.11.7) is not compatible with Python 3.7. If you are using Python 3.7 and still want to use the pybuilder package, you can install the pre-release version (0.12) which is compatible with Python 3.7.
```
pip3 install --pre pybuilder
```

Install Python Packages from Source

Install Python package from a tar.gz file which contains the source code.
```
pip3 install xinstall-0.23.0.tar.gz
```
Install from the current directory
```
pip3 install .
```
pip 20.0+ supports instaling a peotry managed Python project from GitHub directly. For example, the comamnd below installs the Python package dsutil from the GitHub repository dclong/dsutil directly.
```
pip3 install git+ssh://git@github.com/dclong/dsutil 
# or
pip3 install git+https://github.com/dclong/xinstall
# or install with optional components
pip3 install --user -U "dsutil[all] @ git+https://github.com/dclong/dsutil@main"
pip3 install "dsutil[cv] @ file:///home/dclong/dsutil-0.54.1-py3-none-any.whl"
pip3 install "dsutil[cv] @ https://github.com/dclong/dsutil/releases/download/v0.54.1/dsutil-0.54.1-py3-none-any.whl"
```
If you are behind a corporate proxy, you might need 2FA to visit the enterprise GitHub of your company. However, 2FA is usually not required for Git comamnd line (since it would too much hassle). The above way to install Python packages from GitHub repositories directly can be a good way to avoid 2FA authentication if you are behind a corporate proxy.

Install Python Packages from Requirements.txt

You can install Python packages from a requirements.txt file.

pip3 install -r requirements.txt

Notice that all formats accepted by pip3 install is valid in requirements.txt. For example, git+https://github.com/dclong/dsutil@master is valid to use in requirements.txt.

Difference between --ignore-installed and --force-reinstall

Sometimes a package is installed by distutils which cannot be reinstalled using pip, not even with the --force-reinstall option. In that case, you have to use the --ignore-installed option. For more discussions, please refer to Difference Between Pip Install Options Ignore Installed and Force Reinstall and blockstack-core::Issues 504 .

Install Python Packages Without Installing Dependencies

You can install a Python package without installing its dependencies using the command below.

pip3 install --no-deps some_package

Upgrade Python Packages

You can upgrade an already installed Python package to the latest version using the command below.

pip3 install --upgrade wheel

List All Installed Python Packages

List all installed modules.
```
pip3 list
```
List outdated modules only.
```
pip3 list --outdated
```
You can also use help('modules') to show all installed modules in Python.

Use pip with Proxy

You can export environment variables http_proxy and https_proxy or you can use pip with the --proxy option directly.

pip3 --proxy http://proxy__server_ip:port install some_pkg

When using the --proxy with pip/pip3, you can omit http:// and the port if the port is 80.

pip3 --proxy 10.135.227.47 search notifiers

Notice that sometimes pip does not respect the environment variables. In that case, you have to use the option --proxy to pass proxy to pip. And even with the option --proxy, pip might not work well if you install from a version control system. Just be ware of that. ProxyChains is likely a solution when that issue happens.

Misc

pip supports downloading Python packages without installing them. At the same time, you can disable pip caching using the option --no-cache-dir. For more discussions, please refer to Caching .
export LC_ALL=C resolves an issues (cannot remember which issue exactly) of pip3.

Installation Location

Please refer to The Installation Location of Python Packages Using Pip for more discussions.

Check for Existence of a Python Package

https://stackoverflow.com/questions/14050281/how-to-check-if-a-python-module-exists-without-importing-it

The most robust way turns out to be pip3 list, because some packages are namespace sub packagess which are not exposed (visible to importlib) by default. However, all installed packages (via pip) are visible to pip.

pip3 list | grep -i pelican-render-math

References

https://stackoverflow.com/questions/38613316/how-to-upgrade-pip3

https://adamj.eu/tech/2019/03/11/pip-install-from-a-git-repository/

http://stackoverflow.com/questions/36394101/pip-install-locale-error-unsupported-locale-setting

http://unix.stackexchange.com/questions/87745/what-does-lc-all-c-do

https://stackoverflow.com/questions/4888027/python-and-pip-list-all-versions-of-a-package-thats-available

https://stackoverflow.com/questions/5226311/installing-specific-package-versions-with-pip

https://stackoverflow.com/questions/14149422/using-pip-behind-a-proxy

https://stackoverflow.com/questions/9510474/removing-pips-cache

https://stackoverflow.com/questions/36898474/how-to-install-a-module-for-all-users-with-pip-on-linux

How to pip install a package with min and max version range?

How to state in requirements.txt a direct github source

'pip install' From a Git Repository

https://github.com/pypa/pip/issues/4685

https://github.com/pypa/pip/pull/6391

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