Ten Tips for Using Python Pip

Python pip

Let’s start with the Python language. Python is popular not only because it is easy to learn, but also because it has thousands of libraries.

These libraries are equivalent to integrated tools and can be used in Python as long as they are installed. They can handle a wide variety of problems without requiring you to reinvent the wheel, and with constant updates and maintenance by the community, some libraries are becoming more powerful, almost rivaling enterprise-grade applications.

So how to download and install these tool libraries? They are placed in a unified "repository" called PyPi (Python Package Index) from which all library installations originate.

After you have a warehouse, you need an administrator, and pip is such a role. pip takes the library from PyPi and installs it into Python. It can also manage installed libraries such as updating, viewing, searching, uninstalling, etc.

The following summarizes 10 common sense and tips for using pip for your reference.

1. Install pip

Starting from Python 3.4, pip has been built into Python, so there is no need to install it again.

If your Python version does not have pip, you can use the following two methods to install it.

• Enter easy_install pip on the command line, which is very fast.
• Download the pip installation file from the following URL, then extract it to the Python script directory and execute the python setup.py install command.

pip download address: https://pypi.org/project/pip/#files

However, if you are still using Python3.4 and earlier versions, please Upgrade to the latest stable version of Python (https://www.python.org/downloads/). Otherwise, you are adding more technical debt every day.

2. Upgrade pip

If the version of pip is too low, you can upgrade the current version: pip install --upgrade pip or pip install -U pip.

$ pip install -U pip
Looking in indexes: https://pypi.python.org/simple
Requirement already satisfied: pip in ./test/lib/python3.8/site-packages (21.1.1)
Collecting pip
Using cached pip-22.0.4-py3-none-any.whl (2.1 MB)
Installing collected packages: pip
Attempting uninstall: pip
Found existing installation: pip 21.1.1
Uninstalling pip-21.1.1:
Successfully uninstalled pip-21.1.1
Successfully installed pip-22.0.4

3. Installation library

Use pip to install a third-party library. You can execute the following statement: pip install package_name

Specify the package version: pip install package_name==1.1.2

For example, I want to install version 3.4.1 of matplotlib: pip install matplotlib==3.4.1

4. Batch installation of libraries

If a project needs to install many Libraries can be installed in batches: pip install -r requirements.txt

The content format of the file is as follows:

# This is a comment
# Specify a diffrent index
-i http://dist.repoze.org/zope2/2.10/simple
# Package with versions
tensorflow==2.3.1
uvicorn==0.12.2
fastapi==0.63.0
pkg1
pkg2
pkg3>=1.0,<=2.0
# It is possible to refer to specific local distribution paths.
./downloads/numpy-1.9.2-cp34-none-win32.whl
# It is possible to refer to other requirement files or constraints files.
-r other-requirements.txt
-c constraints.txt
# It is possible to specify requirements as plain names.
pytest
pytest-cov
beautifulsoup4

5. Uninstall and upgrade packages

The installed libraries can be used again Uninstall: $ pip uninstall package_name

Version upgrade of the current library:

$ pip install --upgrade package_name

or

$ pip install -U package_name

6. Freeze Python pip dependencies

Sometimes you want to output the current All installed packages in the environment, or generate a requirements file and then install it in another environment through this file. You can use the pip freeze command:

# List packages
$ pip freeze
docutils==0.11
Jinja2==2.7.2
MarkupSafe==0.19
Pygments==1.6
Sphinx==1.2.2
# Generate requirements.txt file
$ pip freeze > requirements.txt

Note that packages are listed in sorted order (case-insensitive). If you only want to list packages that are not installed globally, use -l/--local.

7. View library information

You can use pip show -f package_name to list package information:

$ pip show -f pyyaml
Name: PyYAML
Version: 5.4.1
Summary: YAML parser and emitter for Python
Home-page: https://pyyaml.org/
Author: Kirill Simonov
Author-email: xi@resolvent.net
License: MIT
Location: /private/tmp/test/lib/python3.8/site-packages
Requires:
Required-by: awscli
Files:
PyYAML-5.4.1.dist-info/INSTALLER
PyYAML-5.4.1.dist-info/LICENSE
PyYAML-5.4.1.dist-info/METADATA
PyYAML-5.4.1.dist-info/RECORD
PyYAML-5.4.1.dist-info/WHEEL
PyYAML-5.4.1.dist-info/top_level.txt
...

8. View libraries that need to be upgraded

Among the currently installed libraries, check which libraries need to be upgraded:

$ pip list -o
PackageVersion Latest Type
---------- ------- ------ -----
docutils 0.15.20.18.1 wheel
PyYAML 5.4.1 6.0wheel
rsa4.7.2 4.8wheel
setuptools 56.0.062.1.0 wheel

9. Check compatibility issues

To verify the compatibility dependencies of installed libraries, you can use pip check package-name:

$ pip check awscli
No broken requirements found.

If you do not specify a package name, all packages will be checked for compatibility.

$ pip check
pyramid 1.5.2 requires WebOb, which is not installed.

10. Download the library to the local

Download the library to the specified location locally and save it in whl format: pip download package_name -d "path"

$ pip download PyYAML-d "/tmp/"
Looking in indexes: https://pypi.python.org/simple
Collecting PyYAML
Downloading PyYAML-6.0-cp38-cp38-macosx_10_9_x86_64.whl (192 kB)
 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 192.2/192.2 KB 4.7 MB/s eta 0:00:00
Saved ./PyYAML-6.0-cp38-cp38-macosx_10_9_x86_64.whl
Successfully downloaded PyYAML
$ ls /tmp/PyYAML-6.0-cp38-cp38-macosx_10_9_x86_64.whl
/tmp/PyYAML-6.0-cp38-cp38-macosx_10_9_x86_64.whl

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