I need to run Python 3.8 for my ROS2 installation on Ubuntu 22.04.
When I open Spyder it defaults to Python 3.10.6 and all the scripts work, however when I run Python from the console it uses Python 3.8.15 and no modules are found.
How do I ensure that all pip installations can be seen by Python 3.8?
update-alternatives --config python is set to version 3.8
* 0 /usr/bin/python3.8 3 auto mode
$PATH variable outputs: /home/ros2/ros2_dashing/install/cyclonedds/bin:/home/ros2/ros2_dashing/install/ament_flake8/bin:/home/ros2/ros2_dashing/install/ament_cppcheck/bin:/opt/ros/humble/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/home/ros2/.local/bin
I've found a solution that works for me.
From the console, install each module specifically for the required python version:
python3.8 -m pip install <module>
I am new to Python and Linux env, so a little confused.
I want to find where my Python3.9 is installed, so that I can update the PATH..
Running python --version or python3 --version give me Python 3.6.8
I want to install Python 3.9, so when I run sudo dnf install -y python39 it gives me
Package python39-3.9.12-1ep1.el8.x86_64 is already installed.
ls /usr/bin/python* doesn't show 3.9
Output of above command - /usr/bin/python /usr/bin/python3 /usr/bin/python3.6
/usr/bin/python3.6m
Also tried alternatives --config python but it shows only 3.6
-----------------------------------------------
* 1 /usr/libexec/no-python
+ 2 /usr/bin/python3
which python3.6 gives /usr/bin/python3.6
which python3.9 gives /usr/bin/which: no python3.9 in....
rpm -ql python39-3.9.12-1ep1.el8.x86_64 gives me
/etc/gdbinit.d/python39.gdb. /opt/python3.9.
/opt/python3.9/bin
I could be missing something obvious, if someone can point me in the right direction it will be awesome.
what happens when you enter the following command: python3 --version and is it any different compared to running python --version?
I am not sure what is your actual requirement is. But if you have already installed python 3.9 in your machine, then you can have this and all previous versions applied to different projects. This is selected when you create virtual environments. For example if you want to run a project that built on 3.6, then you can select python interpreter 3.6 at the time of creation.
So the virtual machine I was working was built using vagrant, it had python 3.6 in usr/bin and python 3.9 in opt/python3.9. Newbie like me who wanna understand what /opt is - https://www.baeldung.com/linux/opt-directory
To search any package used command - rpm -ql python39-3.9.12-1ep1.el8.x86_64
Once package is found add it to path as symlinking binaries can be confusing
vim ~/.bashrc
PATH=/opt/python3.9/bin
I am trying to execute a python script that needs img2pdf module.
Note, I already have the Ubuntu package installed for python-img2pdf:
which img2pdf
/usr/bin/img2pdf
Given the following line:
import img2pdf
I get the following:
ModuleNotFoundError: No module named 'img2pdf'
I had only python3.6 version installed before and I have installed python3.9.1 now, After that, I have started getting this error. I think it is something to do with PATH or python default version but after a lot of efforts, I am unable to rectify it.
These are my system details which might help you understand my problem further.
$python -V
Python 3.6.9
$python3 -V
Python 3.9.1
$pip -V
pip 21.0.1 from /usr/local/lib/python3.9/site-packages/pip (python 3.9)
$which python
/usr/bin/python
$which python3
/usr/local/bin/python3
$which pip
/usr/local/bin/pip
Ubuntu 18.04.4
Arm64 arch
Try something like this, I think img2pdf is a shell cmd and cannot be used as a python module ^^
Best regards
deleaf
import os
img2pdf = os.system("img2pdf /path/to/your/image")
https://stackabuse.com/executing-shell-commands-with-python/
I just started setting up a centos server today and noticed that the default version of python on centos is set to 2.6.6. I want to use python 2.7 instead. I googled around and found that 2.6.6 is used by system tools such as YUM so I should not tamper with it. Then I opened up a terminal on my mac and found that I had python 2.6.8 and 2.7.5 and 3.3.3 installed. Sorry for the long story. In short I just want to know how to lookup all the version of python installed on centos so I don't accidentally install it twice.
The more easy way its by executing the next command:
ls -ls /usr/bin/python*
Output look like this:
/usr/bin/python /usr/bin/python2.7 /usr/bin/pythonw
/usr/bin/python-config /usr/bin/python2.7-config /usr/bin/pythonw2.7
we can directly use this to see all the pythons installed both by current user and the root by the following:
whereis python
Find out which version of Python is installed by issuing the command
python --version:
$ python --version
Python 2.7.10
If you see something like this, Python 2.7 is your default version. You can also see if you have Python 3 installed:
$ python3 --version
Python 3.7.2
If you also want to know the path where it is installed, you can issue the command "which" with python and python3:
$ which python
/usr/bin/python
$ which python3
/usr/local/bin/python3
Here is a cleaner way to show them (technically without symbolic links). This includes python2 and python3 installs:
ls -1 /usr/bin/python* | grep '.*[2-3]\(.[0-9]\+\)\?$'
Where grep filters the output of ls that that has that numeric pattern at the end ($).
Or using find:
find /usr/bin/python* ! -type l
Which shows all the different (!) of symbolic link type (-type l).
Use, yum list installed command to find the packages you installed.
COMMAND: python --version && python3 --version
OUTPUT:
Python 2.7.10
Python 3.7.1
ALIAS COMMAND: pyver
OUTPUT:
Python 2.7.10
Python 3.7.1
You can make an alias like "pyver" in your .bashrc file or else using a text accelerator like AText maybe.
As someone mentioned in a comment, you can use which python if it is supported by CentOS. Another command that could work is whereis python. In the event neither of these work, you can start the Python interpreter, and it will show you the version, or you could look in /usr/bin for the Python files (python, python3 etc).
It depends on your default version of python setup. You can query by Python Version:
python3 --version //to check which version of python3 is installed on your computer
python2 --version // to check which version of python2 is installed on your computer
python --version // it shows your default Python installed version.
compgen -c python | grep -P '^python\d'
This lists some other python things too, But hey, You can identify all python versions among them.
Sift through the output of this script.
sudo find / -name 'python*' -type f -exec du -h {} + | sort -r -h ~/Documents/python_locations.txt
ls -l /usr/bin/python* & ls -l /usr/local/bin/python*
I would add to #nurealam siddiq answer,
python --version // it shows your default Python installed version.
python2 --version // to check which version of python2 is installed
python3 --version //to check which version of python3 is installed
python3.X --version // to further check which python3.X is installed
To check python versions installed in your OS you can run the below commands:-
python2 -version
python3 -version
I've installed the Mac OSX Python 2.7.3, and tried switching to the new version:
$ python2.7 -V
Python 2.7.3 # It was installed
$ python -V
Python 2.6.1 # Default is 2.6
$ export VERSIONER_PYTHON_VERSION=2.5
$ python -V
Python 2.5.4 # I can switch to 2.5
$ export VERSIONER_PYTHON_VERSION=2.6
$ python -V
Python 2.6.1 # And 2.6
But:
$ export VERSIONER_PYTHON_VERSION=2.7
$ python -V
python: VERSIONER_PYTHON_VERSION environment variable error (ignored)
Python 2.6.1
Can't switch to 2.7! Why is that?
The python.org install will put a python executable in /usr/local/bin . Apple's python is in /usr/bin
To call the python.org python you can use its full path /usr/local/bin/python or change your path to put /usr/local/bin before /usr/bin. You will still be able to call Apple's python by using its full path /usr/bin/python
Some python installs e.g. Macports provide a tool that provides symbolic links to various python installs and allows you to switch between them.
I don't think we can switch the python version on the Mac OS X without resorting to something like MacPorts or ActivePython.
I think it's because VERSIONER_PYTHON_VERSION is specific to python packages built by apple.