I am having trouble with my current python, so I wanted to uninstall my python and install the latest version. I installed with homebrew, so I uninstalled it with homebrew and reinstalled python 3.8.1 with the installer from the official site. Python3.8 was installed, but my python3 was not upgraded.
~ which python3
/usr/bin/python3
~ python3 --version
Python 3.7.3
I know I'm not supposed to(and I can't) manually delete things inside /usr/bin. What am I supposed to do?
When you installed Python with homebrew it told you this:
Unversioned symlinks python, python-config, pip etc. pointing to
python3, python3-config, pip3 etc., respectively, have been
installed into /usr/local/opt/python/libexec/bin
If you need a reminder, post install, you will get the same message if you run:
brew info python
It says "unversioned links are in /usr/local/opt/python/libexec/bin". That means, if you want to run Python without specifying the version, i.e. if you want to type this:
python
and this:
pip
to start Python 3 and its corresponding pip, you need to make sure your PATH has /usr/local/opt/python/libexec/bin at the start, i.e.
export PATH=/usr/local/opt/python/libexec/bin:$PATH
I could not uninstall the python3 in /usr/bin but found a workaround to give the python3 in /usr/loca/bin precedence by setting the PATH env variable as PATH=/usr/local/bin:$PATH. This gives binaries in /usr/local/bin precedence. Not a full fledged solution, but got me moving.
Related
I have a CentOs system with both Python 2.7 and Python 3.4 installed. I do not have information regarding how these were installed.
However, this is the response when the following commands are issued:
whereis /usr/bin/python3
python3:
/usr/bin/python3.4
/usr/bin/python3.4m
/usr/lib/python3.4
/usr/lib64/python3.4
/usr/include/python3.4m
whereis /usr/bin/python2.7
python2:
/usr/bin/python2.7
/usr/bin/python2
/usr/lib/python2.7
/usr/lib64/python2.7
/usr/include/python2.7
/usr/share/man/man1/python2.1.gz
I am uncertain how to use PIP in this setup. Python documentation for PIP mentions it assumes that your environment is virtual.
If I want to install a module in python3.4 using PIP, what are the steps?
1. sudo as root?
2. set environmental variables?
3. etc...
Installing a Python package is fairly straightforward, you need to first verify that it's not already packaged by your distro, in your case:
yum search <module_name>
Those packages are generally named like: python-<module_name> for a Python 2 module and python3-<module_name> for a Python 3 module.
If it doesn't exist as a package, you can then rely on PyPI:
python3 -m pip install <module_name> --user
From my answer here
Let's break the this command in two parts:
python -m: Allows modules to be located using the Python module namespace for execution as scripts. The motivating examples were standard library modules such as pdb and profile. See PEP 338
--user : By default Python installs Python packages to system directories which requires root privileges, to avoid using sudo pip install (which is not recommended by the way) use this flag to make pip install packages in your home directory instead, which doesn't require any special privileges.
As a side note, if you have multiple versions of Python installed, keeping track of which Python version version pip is bound to can be a PITA, hence python -m, in this case you're sure that it's the pip bound to the Python called which will be executed.
While the previous method works (kinda), it's advised to use virtual environments because many Linux distributions (including CentOs) rely on some Python modules and you don't want to modify them unless you know what you are doing or you absolutely want to break your System.
Additionally, if you only want to "Install and Run Python Applications in Isolated Environments", you can check out pipx.
I always use pip3 when I want to directly refer to python3.
If I want to install a module in python3.4 using PIP, what are the steps? 1. sudo as root? 2. set environmental variables? 3. etc...
just this
sudo apt install python3-pip
pip3 install xyz
If I try to use autopep8 in cygwin (64bit, WIndows10) i get the message "command not found".
$ autopep8
-bash: autopep8: command not found
I tried pip install autopep8 but pip is also not found, only pip2 and pip3.
If I use python -m pip install autopep8 it works so I can call
python -m autopep8
but I want to run a script where just autopep8 is called:
if ! type -p autopep8 >/dev/null; then
echo "autopep8 not found" >&2
autopep8() {
Any ideas how to solve this?
First, you must install PyPi packages to the correct Python installation, and second, you must install the same package to every Python installation in which you want to use it.
Now, a special note about installing Python on Cygwin. You have a choice of several Python versions to install, and scores of packages for use with each of those versions. Avoid Python version 2 unless you have a clearly define reason, as it is post End-of-Life. Instead, install one of the versions of Python 3. As of today, version 3.6 and 3.7 have the more complete sets of optional packages. Version 3.8 beta 4 is available.
For a my install of Python 3.8, I used the Cygwin setup app to install these packages: Python38 (Py3K language interpreter), Python38-pip (Python package installation tool), Python38-setuptools (Python package management tool), Python38-virtualenv (Creates isolated Python environments), and Python38-wheel (Python package format module). To write X11 GUI apps, add Python38-tkinter (Py3K Tkinter GUI module). To install binary packages, add Python38-devel (Py3K language interpreter).
You will be able to install pure Python packages from PyPI. To install binary packages you will also need to have the GNU compiler tool chain installed, and you will need to handle dependencies with other Cygwin packages on your own.
The Python 3.6 and 3.7 installations have addition packages which, in many cases, contain binary packages with the above mentioned dependencies already resolved, or have some useful customizations for the Cygwin environment.
Cygwin has both Python 2 and Python 3. As of today, after installation, you execute Python 2 by python and Python 3 by python3. Be careful which Python you execute as you may get a windows version of Python, if installed, and in your path. which python will always tell where the executable lives, and python -V, etc., will tell you which version you are running. Generally, you want to run a Cygwin version of Python from the bash prompt and Windows versions of Python only from the command prompt or windows GUI.
The safest way to use pip is to use the module version for the Python executable you have chosen, i.e., python -m pip, etc. This avoids having to also remember to use pip with Python and pip3 with Python3.
my computer have python3.4, python3.5, python3.6, python3.7, but now i want to use python virtualenv to create a env , but it show path not found?
The image in here:
You need to provide the full path to Python, for example:
virtualenv.exe -p C:\Python37\python.exe
For git-bash the command should be slightly different:
virtualenv.exe -p /c/Python37/python.exe
First of all having multiple versions of Python is not advised especially if you cant manage them. The issue you are getting stems from the installation of the Virtualenv package. You need to use the python version that has Virtualenv in the site-packages. Examine all the site packages for the 3 versions then use the one that has virtualenv alternatively you can uninstall all the 3 versions and reinstall one I'd advise on Python 3.6 then install virtualenv via pip and try again.
Question
I am not sure why when virtualenv active, pip freeze stills showing all modules when it suppose NOT to. What am I doing wrong?
On the terminal
I tried two ways to create a virtual env:
virtualenv my-virtualenv
virtualenv --no-site-packages my-virtualenv
then activate it
source my-virtualenv/bin/activate
Results
Both show all packages (when they suppose not to). Running command pip freeze I get:
(my-virtualenv)$ pip freeze
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7.
actionlib==1.11.9
angles==1.9.11
bondpy==1.7.19
camera-calibration==1.12.20
camera-calibration-parsers==1.11.12
catkin==0.7.6
cv-bridge==1.12.4
diagnostic-analysis==1.9.2
diagnostic-common-diagnostics==1.9.2
diagnostic-updater==1.9.2
dynamic-reconfigure==1.5.48
gazebo-plugins==2.5.13
gazebo-ros==2.5.13
...
rosnode==1.12.7
rosparam==1.12.7
rospy==1.12.7
rosservice==1.12.7
rostest==1.12.7
rostopic==1.12.7
rosunit==1.13.5
roswtf==1.12.7
tf2-ros==0.5.16
topic-tools==1.12.7
xacro==1.11.2
Running
(my-virtualenv)$ which python
/home/user/.../my-virtualenv/bin/python
(my-virtualenv)$ python -V
Python 2.7.12
and
(my-virtualenv)$ which python3
/usr/bin/python3
(my-virtualenv)$ python3 -V
Python 3.5.2
Hence, I even can use python3 when virtualenv is activated but it uses the pc installed module. Moreover, new installed packages are install in the pc and not the virtualenv and I can't install python3 in the vitualenv because it "exists" already (but in the pc).
I was having the same issue and it was because, somehow, Python configuration of ROS was generating it.
I solved it removing the source commands of ROS from the ~/.bashrc. E.g.:
source /opt/ros/melodic/setup.bash
source $HOME/ROS/aslam_ws/devel/setup.bash
By the way, I realised that, before changing anything, creating the environment from PyCharm works properly too (when in the terminal I still had the issue).
There must be a better solution but I haven't found it yet.
So I've got a virtualenv I've created using pyvenv-3.3, which I thought set up pip to install things into the virtualenv's path. However, I get the following outputs after I've activated by virtualenv:
$ pip --version
pip 1.4.1 from /usr/local/lib/python2.7/site-packages/pip-1.4.1-py2.7.egg (python 2.7)
pip-3.3 --version
pip 1.4.1 from /usr/local/lib/python3.3/site-packages/pip-1.4.1-py3.3.egg (python 3.3)
This is all fine and good, but then my sys.path is this:
['',
'/usr/local/Cellar/python3/3.3.2/Frameworks/Python.framework/Versions/3.3/lib/python33.zip',
'/usr/local/Cellar/python3/3.3.2/Frameworks/Python.framework/Versions/3.3/lib/python3.3',
'/usr/local/Cellar/python3/3.3.2/Frameworks/Python.framework/Versions/3.3/lib/python3.3/plat-darwin',
'/usr/local/Cellar/python3/3.3.2/Frameworks/Python.framework/Versions/3.3/lib/python3.3/lib-dynload',
'/Users/alexgolec/Documents/gutenberg/virtualenv/lib/python3.3/site-packages']
Most notably, the whole site-packages directory is outright missing. Furthermore, this output indicates to me that I'm probably using a python that installed through homebrew at some point. Most infuriatingly, none of the directories in my sys.path are compatible with pip.
Any thoughts on remedies? I won't manually edit my sys.path, but maybe there's some configuration with pip I can do?
Install virtualenvwrapper (makes using virtualenv so much easier):
pip install virtualenvwrapper
.. and then try this:
mkvirtualenv <your_env> -p /usr/local/bin/python3
Where homebrew sticks python is different from where your system has it. You can run the following to see what I'm talking about:
which python
which python3