Python 3.4 command not found - python

I'm trying to do a doctest, I used the cd command in cygwin to navigate to where my .py file is located and then entered this command:
python3 -m doctest file.py
and I get this error in return:
-bash: python3: command not found'.
I'm on Windows 7. I've tried doing the doctest with the file in my Python 3.4 installation directory with no luck, either. I've also tried using the windows command prompt to the same effect. I feel like I'm missing something obvious but I'm not sure what.
EDIT: For future referance, I followed https://docs.python.org/3.3/using/windows.html#finding-the-python-executable and https://docs.python.org/3.3/using/windows.html#setting-envvars to get it to work.

It looks like you're using Cygwin, but haven't installed Cygwin's Python3. Having Windows Python installed isn't enough, and while there are ways of making Cygwin work with Windows Python, doing so has a lot of problems*.
To get Cygwin's Python3, run the Cygwin installer again (download it again if you need to), and select to install "python3" (it's under the "Python" category). Once the installation completes, you should find your command will work.
* Problems off the top of my head include different paths for installed modules, difficulties with line endings, different handling of terminals (i.e. MinTTY vs cmd), and different handling of file globs in the different shells.

(after installing the bare 'python3' package via the installer)
in my cygwin config, python is invoked by default as 'python3'
created an alias in .bashrc thusly :
alias python=python3
problem solved, python now points to the desired version

Related

Can't run any Python files on Ubuntu(WSL)

I have just started working on my new pc and just to get a feel for it I wanted first to start working on python files, so I started first by just wanting to run WSL on windows and it installed correctly but when I want to run any python using the run python file on the top right on VS code, this is what gets executed $ C:/Users/jaffe/AppData/Local/Microsoft/WindowsApps/python3.10.exe f:/Projects/hello.py
And this is the error: -bash: C:/Users/jaffe/AppData/Local/Microsoft/WindowsApps/python3.10.exe: No such file or directory
I have no idea what's causing it but when I run the file using 'Shift + Enter' which is: Python: Run Selection/Line in Python Terminal it seems to run the single line correctly but it gives me this error instead:
print("Hello, world")
-bash: syntax error near unexpected token `"Hello, world"'
but when I run it using python3 hello.py, it works perfectly fine?! I'm so lost as to why this is happening and how could I fix it.
Might be relevant: I'm using windows 10, installed python 3.10.2 from windows store, all of that is in VS code and the python code is one line: print("Hello, world") and I changed the permissions of Local/Microsoft/WindowsApps so it's now accessible by all users to view/read/edit/run, made sure that python3.10.exe exists(on the WindowsApps and it works perfectly) and reinstalled it many times, tired python3.9, and tried to install python from the website instead of the windows store and still the same, manually added python to PATH and tried .venv and didn't work. when I launch python3.10.exe outside vs code it seems to run perfectly, I have worked with python before and it used to work fine now I don't know what's wrong.
I have seen other questions of the same problem I'm having here but none of them solve the problem.
No such file or directory C:/Users/...
For wsl, the Windows filesystem is accessible, but it has a different path. It is mounted under the /mnt folder. So you would find your python .exe under /mnt/c/Users/jaffe/AppData/Local/Microsoft/WindowsApps/python3.10.exe. This said, the executable file is meant to work on Windows, and it doesn't really makes sense to use it on Linux when you could run python within your wsl distro.
python3 works perfectly fine
This is because most Linux distributions come with python3 pre-installed, so you can use it already. To see where it is located, you can run the command which python3, or python3 --version to check its version.
If you want to change version, you may consider download it from you package manager, apt.
I also suggest to install python3-pip if you don't have it already to get the pip package manager for python.
In my case when I ran into this.. I discovered pyenv. This allows you to download more than one version of python. You can then go into a specific directory, such as your python project and issue a python local 3.10.0 (for example). Here's a link on how to install it as well as poetry which is a virtual environment manager that is become very popular. You can also create an alias for python that works off of this. I add this command to my alias file and source it from my .bashrc. alias python='pyenv exec python3'

Adding into Path var while silent installation of Python - possible bug?

I need to passively install Python in my applications package installation so i use the following:
python-3.5.4-amd64.exe /passive PrependPath=1
according this: 3.1.4. Installing Without UI I use the PrependPath parameter which should add paths into Path in Windows environment variables.
But it seems not to work. The variables does not take any changes.
If i start installation manually and select or deselect checkbox with add into Paths then everything works.
Works same with clear installation also on modify current installation. Unfortunately i do not have other PC with Win 10 Pro to test it.
I have also tried it with Python 3.6.3 with same results.
EDIT:
Also tried with PowerShell Start-Process python-3.5.4-amd64.exe -ArgumentList /passive , PretendPath=1 with same results.
Also tested on several PCs with Windows 10, same results, so the problem is not just on single PC
EDIT:
Of cource all attempts were run as administrator.
Ok, from my point of view it seems to be bug in Python Installer and I can not find any way how to make it works.
I have founds the following workaround:
Use py.exe which is wrapper for all version of Python on local machine located in C:\Windows so you can run it directly from CMD anywhere thanks to C:\Windows is standard content of Path variable.
py -3.5 -c "import sys; print(sys.executable[:-10])"
This gives me directory of python 3.5 installation.
And then i set it into Path manually by:
setx Path %UserProfile%";PythonLocFromPreviousCommand
try powershell to do that
Start-Process -NoNewWindow .\python.exe /passive
Make sure you are using an elevated command prompt (ie: run as administrator).
Have you tried to use the InstallAllUsers argument. By default it is set >to 0 so try to use it like this (which is the same example from [here][1]):
python-3.6.0.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0
it migth make a difference to use the /quiet over /passive
[1]: https://docs.python.org
/3.6/using/windows.html#installing-without-ui "the link you supplied"
To answer Erik Šťastný comment i believe that a good solution to your problem is to package python with your program to make sure that all the required libaries is preinstalled.
I also tried the command line options for the python installer and noticed the same issue as you, and here's the solution I found:
Download the 64-bit installer from here: https://www.python.org/downloads/windows/
(the link is titled "Windows x86-64 executable installer")
Uninstall any current python installation.
You can use this command: START python-3.8.3-amd64.exe /uninstall
(replace python-3.8.3-amd64.exe with the name of the file you downloaded).
(run cmd or your batch file as administrator, by right-clicking, then Run As Administrator).
Install (as admin) python 64-bit for all users, with the START command:
START python-3.8.3-amd64.exe /passive PrependPath=1 Include_pip=1 InstallAllUsers=1
(replace python-3.8.3-amd64.exe with the name of the file you downloaded).
(run cmd or your batch file as administrator, by right-clicking, then Run As Administrator).
(More info on python installer command line options: https://docs.python.org/3/using/windows.html#installing-without-ui).
(Optional) Open a new cmd window to verify that python works from any location:
You can run this command:python --version
(If you don't see output like "Python 3.8.3", then Python has not been added to your PATH).
(Note: That command didn't work until I opened a new command prompt window).
For me, all of the details were important, so don't skip any.

Python in Cygwin

I would like to know the difference in
installing Python, Paramiko packages in Cygwin and
Python is already installed in my Windows PC. I have installed Cygwin too (but without Python package) and in Cygwin terminal I do the following:
$echo "PATH=\$PATH:/cygdrive/c/Python27" >> .bash_profile
then,
source .bash_profile (after doing this I am able to run a Python script from cygwin terminal).
If the steps in point number 2 works good, then still do I need to install python packages from a Cygwin mirror site ? If I have not done it, then what I might miss while running Python through Cygwin ?
Thanks for your help.
No, you don't need to do so. In fact, CYGWIN will inherit the PC's PATH, plus with virtual PATH, you can input "echo $PATH" in CYGWIN and input "PATH" and the windows console, you could find that CYGWIN has more PATH setting than the windows. However, as you already overwrite the bash_profile, so it might not looks as what I said.
Besides, the most significant difference is that most of the CYGWIN executable files depends on CYGWIN.dll, while the typically windows files don't.
To use Python in Cygwin, you add this line to .bash_profile file.
export PATH=$PATH:/cygdrive/c/virtualenv/python2.7/Scripts
Hope for helps.

How to install both Python 2.x and Python 3.x in Windows

I do most of my programming in Python 3.x on Windows 7, but now I need to use the Python Imaging Library (PIL), ImageMagick, and wxPython, all of which require Python 2.x.
Can I have both Python 2.x and Python 3.x installed in Windows 7? When I run a script, how would I "choose" which version of Python should run it? Will the aforementioned programs be able to handle multiple versions of Python installed at once? I have searched for hours and hours for how to do this to no avail.
Thanks.
I found that the formal way to do this is as follows:
Just install two (or more, using their installers) versions of Python on Windows 7 (for me work with 3.3 and 2.7).
Follow the instuctions below, changing the parameters for your needs.
Create the following environment variable (to default on double click):
Name: PY_PYTHON
Value: 3
To launch a script in a particular interpreter, add the following shebang (beginning of script):
#! python2
To execute a script using a specific interpreter, use the following prompt command:
> py -2 MyScript.py
To launch a specific interpreter:
> py -2
To launch the default interpreter (defined by the PY_PYTHON variable):
> py
Resources
Documentation: Using Python on Windows
PEP 397 - Python launcher for Windows
What I did was download both 2.7.6 and 3.3.4. Python 3.3.4 has the option to add the path to it in the environment variable so that was done. So basically I just manually added Python 2.7.6.
How to...
Start > in the search type in environment select "Edit environment variables to your account"1
Scroll down to Path, select path, click edit.
Add C:\Python27;
so you should have paths to both versions of Python there, but if you don't this you can easily edit it so that you do..... C:\Python27;C:\Python33;
Navigate to the Python27 folder in C:\ and rename a copy of python.exe to python2.exe
Navigate to the Python34 folder in C:\ and rename a copy of python.exe to python3.exe
Test: open up commmand prompt and type python2 ....BOOM! Python 2.7.6. exit out.
Test: open up commmand prompt and type python3 ....BOOM! Python 3.4.3. exit out.
Note: (so as not to break pip commands in step 4 and 5, keep copy of python.exe in the same directory as the renamed file)
I have multiple versions in windows.
I just change the exe name of the version I'm not defaulting to.
python.exe --> python26.exe
pythonw.exe --> pythonw26.exe
As for package installers, most exe installers allow you to choose the python install to add the package too.
For manual installation check out the --prefix option to define where the package should be installed:
http://docs.python.org/install/index.html#alternate-installation-windows-the-prefix-scheme
If you use Anaconda Python, you can easily install various environments.
Say you had Anaconda Python 2.7 installed and you wanted a python 3.4 environment:
conda create -n py34 python=3.4 anaconda
Then to activate the environment:
activate py34
And to deactive:
deactivate py34
(With Linux, you should use source activate py34.)
Links:
Download Anaconda Python
Instructions for environments
To install and run any version of Python in the same system follow my guide below.
For example say you want to install Python 2.x and Python 3.x on the same Windows system.
Install both of their binary releases anywhere you want.
When prompted do not register their file extensions and
do not add them automatically to the PATH environment variable
Running simply the command python the executable that is first met in PATH will be chosen for launch. In other words, add the Python directories manually. The one you add first will be selected when you type python. Consecutive python programs (increasing order that their directories are placed in PATH) will be chosen like so:
py -2 for the second python
py -3 for the third python etc..
No matter the order of "pythons" you can:
run Python 2.x scripts using the command: py -2 (Python 3.x functionality) (ie. the first Python 2.x installation program found in your PATH will be selected)
run Python 3.x scripts using the command: or py -3 (ie. the first Python 3.x installation program found in your PATH will be selected)
In my example I have Python 2.7.14 installed first and Python 3.5.3. This is how my PATH variable starts with:
PATH=C:\Program Files\Microsoft MPI\Bin\;C:\Python27;C:\Program Files\Python_3.6\Scripts\;C:\Program Files\Python_3.6\;C:\ProgramData\Oracle\Java\javapath;C:\Program Files (x86)\Common Files\Intel\Shared
...
Note that Python 2.7 is first and Python 3.5 second.
So running python command will launch python 2.7 (if Python 3.5 the same command would launch Python 3.5).
Running py -2 launches Python 2.7 (because it happens that the second Python is Python 3.5 which is incompatible with py -2).
Running py -3 launches Python 3.5 (because it's Python 3.x)
If you had another python later in your path you would launch like so: py -4. This may change if/when Python version 4 is released.
Now py -4 or py -5 etc. on my system outputs: Requested Python version (4) not installed or Requested Python version (5) not installed etc.
Hopefully this is clear enough.
Here's what you can do:
Install cmder.
Open and use Cmder as you would with you cmd terminal.
Use the command alias to create command aliases.
I did the following:
alias python2 = c:\python27\python.exe
alias python3 = c:\python34\python.exe
And that's it! ;-)
I actually just thought of an interesting solution. While Windows will not allow you to easily alias programs, you can instead create renamed batch files that will call the current program.
Instead of renaming the executable which will break a lot of thing including pip, create the file python2.bat in the same directory as the python2.exe. Then add the following line:
%~dp0python %*
What does this archaic syntax mean? Well, it's a batch script, (Windows version of bash). %~dp0 gets the current directory and %* will just pass all the arguments to python that were passed to the script.
Repeat for python3.bat
You can also do the same for pip and other utilities, just replace the word python in the file with pip or whathever the filename. The alias will be whatever the file is named.
Best of all, when added to the PATH, Windows ignores the extension so running
python3
Will launch the python3 version and and the command python2 will launch the python2 version.
BTW, this is the same technique Spyder uses to add itself to the path on Windows. :)
Starting version 3.3 Windows version has Python launcher, please take a look at section 3.4. Python Launcher for Windows
You can install multiple versions of Python one machine, and during setup, you can choose to have one of them associate itself with Python file extensions. If you install modules, there will be different setup packages for different versions, or you can choose which version you want to target. Since they generally install themselves into the site-packages directory of the interpreter version, there shouldn't be any conflicts (but I haven't tested this). To choose which version of python, you would have to manually specify the path to the interpreter if it is not the default one. As far as I know, they would share the same PATH and PYTHONPATH variables, which may be a problem.
Note: I run Windows XP. I have no idea if any of this changes for other versions, but I don't see any reason that it would.
What I have done on my own windows computer where I have Python 2.7 and Python 3.4 installed is I wrote a simple .bat file in the same directory as my Python.exe files. They look something like,
cmd /k "c:\python27\python.exe" %*
The %* allows you to add arguments (Python files) afterwards. I believe /k keeps the prompt open after it finishes running the script. Then I save that as python27.bat Then I go to my Python 3 directory and make a bat file there. Now in my command line I can write
Python27 helloworld.py
Or
Python34 helloworld.py
And they will run in their respective versions of Python. Make sure that c:\python27 and c:\python34 are in your environment variables.
I got my answer from here
I did this in three steps by following the instructions here: This is all taken directly from here: http://ipython.readthedocs.io/en/stable/install/kernel_install.html. I'm currently running Python 2.x on Windows 8 and have Anaconda 4.2.13 installed.
1) First install the latest version of python:
conda create -n python3 python=3 ipykernel
2) Next activate python3
activate python3
3) Install the kernel:
python -m ipykernel install --user
If you have Python 3 installed and want to install 2, switch the 2 and the 3 above. When you open a new notebook, you can now choose between Python 2 or 3.
Check your system environment variables after installing Python, python 3's directories should be first in your PATH variable, then python 2.
Whichever path variable matches first is the one Windows uses.
As always py -2 will launch python2 in this scenario.
I have encountered that problem myself and I made my launchers in a .bat so you could choose the version you want to launch.
The only problem is your .py must be in the python folder, but anyway here is the code:
For Python2
#echo off
title Python2 Launcher by KinDa
cls
echo Type the exact version of Python you use (eg. 23, 24, 25, 26)
set/p version=
cls
echo Type the file you want to launch without .py (eg. hello world, calculator)
set/p launch=
path = %PATH%;C:\Python%version%
cd C:\Python%version%
python %launch%.py
pause
For Python3
#echo off
title Python3 Launcher by KinDa
cls
echo Type the exact version of Python you use (eg. 31, 32, 33, 34)
set/p version=
cls
echo Type the file you want to launch without .py (eg. hello world, calculator)
set/p launch=
cls
set path = %PATH%:C:\Python%version%
cd C:\Python%version%
python %launch%.py
pause
Save them as .bat and follow the instructions inside.
Install the one you use most (3.3 in my case) over the top of the other. That'll force IDLE to use the one you want.
Alternatively (from the python3.3 README):
Installing multiple versions
On Unix and Mac systems if you intend to install multiple versions of Python
using the same installation prefix (--prefix argument to the configure script)
you must take care that your primary python executable is not overwritten by the
installation of a different version. All files and directories installed using
"make altinstall" contain the major and minor version and can thus live
side-by-side. "make install" also creates ${prefix}/bin/python3 which refers to
${prefix}/bin/pythonX.Y. If you intend to install multiple versions using the
same prefix you must decide which version (if any) is your "primary" version.
Install that version using "make install". Install all other versions using
"make altinstall".
For example, if you want to install Python 2.6, 2.7 and 3.3 with 2.7 being the
primary version, you would execute "make install" in your 2.7 build directory
and "make altinstall" in the others.
I just had to install them. Then I used the free (and portable) soft at http://defaultprogramseditor.com/ under "File type settings"/"Context menu"/search:"py", chose .py file and added an 'open' command for the 2 IDLE by copying the existant command named 'open with IDLE, changing names to IDLE 3.4.1/2.7.8, and remplacing the files numbers of their respective versions in the program path. Now I have just to right click the .py file and chose which IDLE I want to use. Can do the same with direct interpreters if you prefer.
I use a simple solution to switch from a version to another version of python, you can install all version you want. All you have to do is creating some variable environment.
In my case, I have installed python 2.7 and python 3.8.1, so I have created this environment variables:
PYTHON_HOME_2.7=<path_python_2.7>
PYTHON_HOME_3.8.1=<path_python_3.8.1>
PYTHON_HOME=%PYTHON_HOME_2.7%
then in my PATH environment variable I put only %PYTHON_HOME% and %PYTHON_HOME%\Scripts. In the example above I'm using the version 2.7, when I want to switch to the other version I have only to set the PYTHON_HOME=%PYTHON_HOME_3.8.1%.
I use this method to switch quickly from a version to another also for JAVA, MAVEN, GRADLE,ANT, and so on.
Only Works if your running your code in your Python IDE
I have both Python 2.7 and Python 3.3 installed on my windows operating system. If I try to launch a file, it will usually open up on the python 2.7 IDE. How I solved this issue, was when I choose to run my code on python 3.3, I open up python 3.3 IDLE(Python GUI), select file, open my file with the IDLE and save it. Then when I run my code, it runs to the IDLE that I currently opened it with. It works vice versa with 2.7.
I have installed both python 2.7.13 and python 3.6.1 on windows 10pro and I was getting the same "Fatal error" when I tried pip2 or pip3.
What I did to correct this was to go to the location of python.exe for python 2 and python 3 files and create a copy of each, I then renamed each copy to python2.exe and python3.exe depending on the python version in the installation folder. I therefore had in each python installation folder both a python.exe file and a python2.exe or python3.exe depending on the python version.
This resolved my problem when I typed either pip2 or pip3.
If you can't get anything else to work, open an interpreter in whichever version you choose (I prefer using iPython) and:
import subprocess
subprocess.call('python script.py -flags')
This uses whichever python version you are currently operating under. Works fine for a single script, but will quickly get out of hand if there are lots of scripts you run, in which case you can always make a batch file with all of these calls inside. Not the most elegant answer, but it works.
Is there a way to make aliases for different python version a la Linux?

Running a python script from the command line in Windows

I'm trying to run SnakeFood, to analyze a python project. I'm on a Windows machine and so far I've been able to figure out how to:
install Tortoise for Mercurial to download the SnakeFood code from the site
set the windows Path to accept python from the command prompt so I could do python setup.py install and got snakefood to go into my "site-packages" folder
Now, the documentation doesn't say anything else rather than:
sfood /path/to/my/project
I can't get this command to work. What am I missing?
Would this work?
python "DriveLetter:\path\to\sfood.py" "DriveLetter:\path\to\your\project"
Considering the documentation says "sfood /path/to/my/project" it most likely assumes a *nix environment. That leads me to the assumption that sfood probably has a shebang line.
On Windows you probably need to use "python sfood ". If "sfood" isn't in your PATH, you'll need to write the full path rather than just "sfood".
I was able to resolve this issue, on my Windows 7 machine with Python 2.7.3 installed, like so:
C:\> cd \path\to\snakefood\installation\folder
C:\path\to\snakefood\installation\folder> python setup.py install
...
C:\path\to\snakefood\installation\folder> cd C:\Python27\Scripts
C:\Python27\Scripts> python sfood \path\to\my\project
...

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