how to manage multiple Python distributions on one device - python

I have a macbook pro, and I have Python 2.7,3.3 and 3.4 and Anaconda 2.7 installed, and I am having a hard time managing all these multiple Python distributions. These are the problems I am facing :
pip install installs for anaconda 2.7 by default, how do I make it install for PYthon 2.7 ?
how do I make pip3 install work for different Python distributions? i.e is there some way I can use something like pip3 install -v 3.3.6 or something similar.
how do I find a workaround for these problems. I wish to know the answer in both the basic sense (how Python and Anaconda work, and what happens when I use pip install, and how do I use these to solve my problem), and also in the practical sense (is there some simple way to manage this problem).

To install packages for specific python versions, it is easiest to run python with the -m flag. The -m flag will run the specified module as a script. Calling python -m pip install _package_ will run pip for whatever python you specify.
Examples:
python -m pip install _package_
python3 -m pip install _package_
python2.7 -m pip install _package_
python3.7 -m pip install _package_

Related

python: pip fails to install matplotlib v.3.1.1 [duplicate]

On Ubuntu 10.04 by default Python 2.6 is installed, then I have installed Python 2.7. How can I use pip install to install packages for Python 2.7.
For example:
pip install beautifulsoup4
by default installs BeautifulSoup for Python 2.6
When I do:
import bs4
in Python 2.6 it works, but in Python 2.7 it says:
No module named bs4
Alternatively, since pip itself is written in python, you can just call it with the python version you want to install the package for:
python2.7 -m pip install foo
Use a version of pip installed against the Python instance you want to install new packages to.
In many distributions, there may be separate python2.6-pip and python2.7-pip packages, invoked with binary names such as pip-2.6 and pip-2.7. If pip is not packaged in your distribution for the desired target, you might look for a setuptools or easyinstall package, or use virtualenv (which will always include pip in a generated environment).
pip's website includes installation instructions, if you can't find anything within your distribution.
You can execute pip module for a specific python version using the corresponding python:
Python 2.6:
python2.6 -m pip install beautifulsoup4
Python 2.7
python2.7 -m pip install beautifulsoup4
In Windows, you can execute the pip module by mentioning the python version ( You need to ensure that the launcher is on your path )
py -2 -m pip install pyfora
You can use this syntax
python_version -m pip install your_package
For example. If you're running python3.5, you named it as "python3", and want to install numpy package
python3 -m pip install numpy
Have tried this on a Windows machine and it works
If you wanna install opencv for python version 3.7, heres how you do it!
py -3.7 -m pip install opencv-python
Alternatively, if you want to install specific version of the package with the specific version of python, this is the way
sudo python2.7 -m pip install pyudev=0.16
if the "=" doesnt work, use ==
x#ubuntuserv:~$ sudo python2.7 -m pip install pyudev=0.16
Invalid requirement: 'pyudev=0.16'
= is not a valid operator. Did you mean == ?
x#ubuntuserv:~$ sudo python2.7 -m pip install pyudev==0.16
works fine
If you have both 2.7 and 3.x versions of python installed, then just rename the python exe file of python 3.x version to something like - "python.exe" to "python3.exe". Now you can use pip for both versions individually. If you normally type "pip install " it will consider the 2.7 version by default. If you want to install it on the 3.x version you need to call the command as "python3 -m pip install ".
Python 2
sudo pip2 install johnbonjovi
Python 3
sudo pip3 install johnbonjovi
For Python 3
sudo apt-get install python3-pip
sudo pip3 install beautifulsoup4
For Python 2
sudo apt-get install python2-pip
sudo pip2 install beautifulsoup4
On Debian/Ubuntu, pip is the command to use when installing packages
for Python 2, while pip3 is the command to use when installing
packages for Python 3.
for python2 use:
py -2 -m pip install beautifulsoup4
I faced a similar problem with another package called Twisted. I wanted to install it for Python 2.7, but it only got installed for Python 2.6 (system's default version).
Making a simple change worked for me.
When adding Python 2.7's path to your $PATH variable, append it to the front like this: PATH=/usr/local/bin:$PATH, so that the system uses that version.
If you face more problems, you can follow this blog post which helped me - https://github.com/h2oai/h2o-2/wiki/installing-python-2.7-on-centos-6.3.-follow-this-sequence-exactly-for-centos-machine-only
As with any other python script, you may specify the python installation you'd like to run it with. You may put this in your shell profile to save the alias. The $1 refers to the first argument you pass to the script.
# PYTHON3 PIP INSTALL V2
alias pip_install3="python3 -m $(which pip) install $1"
I'm using Ubuntu 22.04, which comes with python 3.10.4.
Some packages do not have recent pip packages, so I needed install from an older pip. This sequence worked for me.
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.9
sudo apt install python3.9-distutils
python3.9 -m pip install onnxruntime-gpu
Folder location: /usr/local/lib/python3.8
Package: python3.8 -m pip install <package_name>
I had Python 2.7 installed via chocolatey on Windows and found pip2.7.exe in C:\tools\python2\Scripts.
Using this executable instead of the pip command installed the correct module for me (requests for Python 2.7).
I think the best practice here is not to use the system python or install any system python package (no apt install). That is just the way to trouble.
Instead, build the required Python version from source, get it installed in /usr/local/... . Then use pip to install packages for that. It is really not that hard to build Python from source on Ubuntu.
sudo apt install build-essential
download the source from https://www.python.org/downloads/source/
unpack the file downloaded: tar xf <filename>
cd <directory> - change into the directory created.
./configure
make
sudo make install
Then check /usr/local/bin for a pip script tied to that version. Use that to pip install whatever you need. Also find the particular executable for the python version in that directory. You might have to shuffle things a bit if you get lots of versions.
Again, do not mess with system python.

Install OpenCV for systemwide Python on MacOS

I have three versions of python:
python (2.7.10, default systemwide version shipped with MacOS)
python2 (2.7.15, installed with brew)
python3 (3.6.5, installed with brew)
I installed opencv for python2 and python3 using pip2 and pip3, respectively. However, I have a matlab application (VOT-toolkit) which generates a command as: /usr/bin/python -c "import cv2" which fails since /usr/bin/python refers to the systemwide python version which does not have opencv installed.
Is there a way I can install opencv for the systemwide python version? (If possible, directly using pip without having to build from sources)
Thanks!
Probably your pip2 points to the newer installation. One can use the specific pip of the installation or one can invoke pip using python. I prefer the later, since this is 100% certain that it will be installed for the correct python installation. To do it, you only need the path to the python installation which you want to use and write the following code:
/path/to/python -m pip install package
or in your case:
/usr/bin/python -m pip install opencv-python
In some weird cases pip is not install and you can do (python >= 2.7.9 or 3.4):
/usr/bin/python -m ensurepip
You may need permission to use this command so you can do it with sudo or any other way to ensure the permissions are met.

How do I install biopython for a specific version of python

I have attempted to install biopython for python2.7 on a cluster of machines.
I have a tonne of scripts that are written in python2.7 and I need to use biopython, but the refactoring of the scripts is more hassle than it is worth - so I thought it would be easier to use an install workaround.
pip install python2 biopython
and
pip install python2.7 biopython
and all variations of these calls do nothing.
They tell me everything is satisfied because there is an installation of biopython for python3.4.
Does anyone know this installation command?
Since version 0.8 you can use the following:
$ pip-2.5 install package
$ pip-2.6 install package
$ pip-2.7 install package
Also see this question: pip: dealing with multiple Python versions?

How to use pip with python3.5 after upgrade from 3.4?

I'm on Ubuntu and I have python2.7, (it came pre-installed) python3.4, (used before today) and python3.5, which I upgraded to today, installed in parallel. They all work fine on their own.
However, I want to use pip to install some packages, and I can't figure out how to do this for my 3.5 installation because pip installs for 2.7 and pip3 installs python 3.4 packages.
For instance, I have asyncio installed on 3.4, but I can't import it from 3.5. When I do pip3 install aysncio, it tells me the requirement is already satisfied.
I'm a bit of a newbie, but I did some snooping around install directories and couldn't find anything and I've googled to no avail.
I suppose you can run pip through Python until this is sorted out. (https://docs.python.org/dev/installing/)
A quick googling seems to indicate that this is indeed a bug. Try this and report back:
python3.4 -m pip --version
python3.5 -m pip --version
If they report different versions then I guess you're good to go. Just run python3.5 -m pip install package instead of pip3 install package to install 3.5 packages.
Another way would be to setup a virtual environment:
$ python3.4 -m venv envdir
$ source envdir/bin/activate
$ pip --version
Obviously, this won't install the packages globally and you'll have to source venv/bin/activate every time you wan to make use of it.

how can i use pip with pypy installed from launchpad?

I have ubuntu 11.10. I apt-get installed pypy from this launchpad repository: https://launchpad.net/~pypy the computer already has python on it, and python has its own pip. How can I install pip for pypy and how can I use it differently from that of python?
Quoting (with minor changes) from here the pypy website:
If you want to install 3rd party libraries, the most convenient way is
to install pip:
$ curl -O https://bootstrap.pypa.io/get-pip.py
$ ./pypy-2.1/bin/pypy get-pip.py
$ ./pypy-2.1/bin/pip install pygments # for example
In order to use it nicely, you might want to add an alias into e.g. ~/.bashrc:
alias pypy_pip='./pypy-2.1/bin/pip'
Where the actual pip executable is located has to be taken from the output of pypy get-pip.py
To keep a separate installation, you might want to create a virtualenv for PyPy. Within the virtualenv, you can then just run pip install whatever and it will install it for PyPy. When you create a virtualenv, it automatically installs pip for you.
Otherwise, you will need to work out where PyPy will import from and install distribute and pip in one of those locations. pip's installer should do this automatically when run with PyPy. Be careful with this option - if it decides to install in your system Python directories, it could break other things.
if you want to use pip with pypy:
pypy -m pip install [package]
pip is included with pypy so just target pip with the -m flag
The problem with pip installing from the pypy (at least when installing pypy via apt-get) is that it is installed into the system path:
$ whereis pip
pip: /usr/local/bin/pip /usr/bin/pip
So after such install, pypy pip is executed by default (/usr/local/bin/pip) instead of the python pip (/usr/bin/pip) which may break subsequent updates of the whole Ubuntu.
The problem with virtualenv is that you should remember where and what env you created.
Convenient alternative solution is conda (miniconda), which manages not only python deployments: http://conda.pydata.org/miniconda.html.
Comparison of conda, pip and virtualenv:
http://conda.pydata.org/docs/_downloads/conda-pip-virtualenv-translator.html

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