What happens when "pip install <package name>" - python

What are the sequence of steps when we do
$ pip install <package name>
More specific questions
How does pip find the package?
Where does pip store the package?
How to uninstall the package?

1. How does pip find the package?
On the web, from the official repository PyPI (Python Package Index). A complete list of all packages can be found here.
2. Where does pip store the package?
They are installed in your Python directory, depends of your OS. Search about PYTHON_PATH/Lib/sites-packages, you may found packages install through pip :)
3. How to uninstall the package?
pip uninstall <package-name>

In the Python Package Index a.k.a. PyPI.
In your Python installation's Lib\site-packages directory.
Usually with pip uninstall <package-name>

Related

pip install -find-links search order

I am trying to install a package built by myself, but there is a package with same name on PYPI.
I tried with pip install my_package==1.2.0 --find-links page_html_with_link_to_package, but it downloaded the package from PYPI with same version 1.2.0.
Then I tried with pip install my_package==1.2.0 --find-links page_html_with_link_to_package --no-index, and it downloaded my package.
It's that normal? And if there is any other ways to download my package without --no-index?
Thanks!
Yes, this is normal. Check these examples below on official documentation of pip install, example 9. Install from alternative package repositories > Install from a local flat directory containing archives (and don’t scan indexes):
pip install --no-index --find-links=file:///local/dir/ SomePackage
pip install --no-index --find-links=/local/dir/ SomePackage
pip install --no-index --find-links=relative/dir/ SomePackage
or if you have it hosted somewhere else, then you can just use:
pip install --index-url http://my.package.repo/simple/ SomePackage

How can pip know a package's last version?

I use pip to manage my packages, but how can I know a package's newest version?
I use the
pip install --upgrade eventlet
find the result the version did not change. still is eventlet (0.21.0).
But in the GitHub, you see the doc the newest version is v0.22.1.
If a package is not updated on pypi, you cannot pip install packagename to get the latest version. If you absolutely want the latest version you can install it directly from git
git clone <git URL of library>
cd into the directory and install the package:
sudo python setup.py install
if you want to get the list of all the modules that can be updated i.e. the modules with updated available you can use:
pip list --outdated
This will give you the output like
....
ipython (6.2.1) - Latest: 6.3.1 [wheel]
....
allowing you to chose the packages you want to update

Uninstall a package installed with `pip install .`

When installing Python packages from development repositories, I usually navigate to wherever setup.py is found and do
pip install .
This installs the package in $HOME/.local/. Nice.
How can I uninstall a package installed this way?
Simply run pip uninstall package-name
That's all you need.
For more follow this link : https://pip.pypa.io/en/stable/reference/pip_uninstall/

How to uninstall packages installed using setuptools

That's it, I've some package installed using setuptools i.e. I ran the command python setup.py install from the package source.
My question is, how do I uninstall the package or upgrade it?
Install pip using easy_install:
easy_install pip
and then:
pip uninstall <package>
PS. Probably duplicate.

Installing specific package version with pip

I am trying to install version 1.2.2 of MySQL_python, using a fresh virtualenv created with the --no-site-packages option. The current version shown in PyPi is 1.2.3. Is there a way to install the older version? I have tried:
pip install MySQL_python==1.2.2
However, when installed, it still shows MySQL_python-1.2.3-py2.6.egg-info in the site packages. Is this a problem specific to this package, or am I doing something wrong?
TL;DR:
Update as of 2022-12-28:
pip install --force-reinstall -v
For example: pip install --force-reinstall -v "MySQL_python==1.2.2"
What these options mean:
--force-reinstall is an option to reinstall all packages even if they are already up-to-date.
-v is for verbose. You can combine for even more verbosity (i.e. -vv) up to 3 times (e.g. --force-reinstall -vvv).
Thanks to #Peter for highlighting this (and it seems that the context of the question has broadened given the time when the question was first asked!), the documentation for Python discusses a caveat with using -I, in that it can break your installation if it was installed with a different package manager or if if your package is/was a different version.
Original answer:
pip install -Iv (i.e. pip install -Iv MySQL_python==1.2.2)
What these options mean:
-I stands for --ignore-installed which will ignore the installed packages, overwriting them.
-v is for verbose. You can combine for even more verbosity (i.e. -vv) up to 3 times (e.g. -Ivvv).
For more information, see pip install --help
First, I see two issues with what you're trying to do. Since you already have an installed version, you should either uninstall the current existing driver or use pip install -I MySQL_python==1.2.2
However, you'll soon find out that this doesn't work. If you look at pip's installation log, or if you do a pip install -Iv MySQL_python==1.2.2 you'll find that the PyPI URL link does not work for MySQL_python v1.2.2. You can verify this here: http://pypi.python.org/pypi/MySQL-python/1.2.2
The download link 404s and the fallback URL links are re-directing infinitely due to sourceforge.net's recent upgrade and PyPI's stale URL.
So to properly install the driver, you can follow these steps:
pip uninstall MySQL_python
pip install -Iv http://sourceforge.net/projects/mysql-python/files/mysql-python/1.2.2/MySQL-python-1.2.2.tar.gz/download
You can even use a version range with pip install command. Something like this:
pip install 'stevedore>=1.3.0,<1.4.0'
And if the package is already installed and you want to downgrade it add --force-reinstall like this:
pip install 'stevedore>=1.3.0,<1.4.0' --force-reinstall
One way, as suggested in this post, is to mention version in pip as:
pip install -Iv MySQL_python==1.2.2
i.e. Use == and mention the version number to install only that version. -I, --ignore-installed ignores already installed packages.
To install a specific python package version whether it is the first time, an upgrade or a downgrade use:
pip install --force-reinstall MySQL_python==1.2.4
MySQL_python version 1.2.2 is not available so I used a different version. To view all available package versions from an index exclude the version:
pip install MySQL_python==
I believe that if you already have a package it installed, pip will not overwrite it with another version. Use -I to ignore previous versions.
Sometimes, the previously installed version is cached.
~$ pip install pillow==5.2.0
It returns the followings:
Requirement already satisfied: pillow==5.2.0 in /home/ubuntu/anaconda3/lib/python3.6/site-packages (5.2.0)
We can use --no-cache-dir together with -I to overwrite this
~$ pip install --no-cache-dir -I pillow==5.2.0
Since this appeared to be a breaking change introduced in version 10 of pip, I downgraded to a compatible version:
pip install 'pip<10'
This command tells pip to install a version of the module lower than version 10. Do this in a virutalenv so you don't screw up your site installation of Python.
This below command worked for me
Python version - 2.7
package - python-jenkins
command - $ pip install 'python-jenkins>=1.1.1'
I recently ran into an issue when using pip's -I flag that I wanted to document somewhere:
-I will not uninstall the existing package before proceeding; it will just install it on top of the old one. This means that any files that should be deleted between versions will instead be left in place. This can cause weird behavior if those files share names with other installed modules.
For example, let's say there's a package named package. In one of packages files, they use import datetime. Now, in package#2.0.0, this points to the standard library datetime module, but in package#3.0.0, they added a local datetime.py as a replacement for the standard library version (for whatever reason).
Now lets say I run pip install package==3.0.0, but then later realize that I actually wanted version 2.0.0. If I now run pip install -I package==2.0.0, the old datetime.py file will not be removed, so any calls to import datetime will import the wrong module.
In my case, this manifested with strange syntax errors because the newer version of the package added a file that was only compatible with Python 3, and when I downgraded package versions to support Python 2, I continued importing the Python-3-only module.
Based on this, I would argue that uninstalling the old package is always preferable to using -I when updating installed package versions.
There are 2 ways you may install any package with version:-
A). pip install -Iv package-name == version
B). pip install -v package-name == version
For A
Here, if you're using -I option while installing(when you don't know if the package is already installed) (like 'pip install -Iv pyreadline == 2.* 'or something), you would be installing a new separate package with the same existing package having some different version.
For B
At first, you may want to check for no broken requirements.
pip check
2.and then see what's already installed by
pip list
3.if the list of the packages contain any package that you wish to install with specific version then the better option is to uninstall the package of this version first, by
pip uninstall package-name
4.And now you can go ahead to reinstall the same package with a specific version, by
pip install -v package-name==version
e.g. pip install -v pyreadline == 2.*
If you want to update to latest version and you don't know what is the latest version you can type.
pip install MySQL_python --upgrade
This will update the MySQL_python for latest version available, you can use for any other package version.
dependency packaging has had a new release, wherein it has dropped LegacyVersion from its codebase
The quick solution might be pin packaging==21.3

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