I'm trying to run a Python program, which uses the pygame modules, from MATLAB. I know I can use either
system('python program.py')
or just
! python program.py
However, I keep getting the error:
Traceback (most recent call last):
File "program.py", line 1, in <module>
import pygame
ImportError: No module named pygame
What is strange is that if I run the program from the command line, it works just fine. Does anyone know why if run from within MATLAB, Python can't find pygame?
The problem may be that MATLAB is not seeing your PYTHONPATH, which normally stores Python libraries and modules. For custom modules, PYTHONPATH should also include the path to your custom folders.
You can try setting the value of PYTHONPATH from within a MATLAB running session:
PATH_PYTHON = '<python_lib_folder>'
setenv('PYTHONPATH', PATH_PYTHON); % set env path (PYTHONPATH) for this session
system('python program.py');
See also the possibly relevant SO answer here: How can I call a Qtproject from matlab?
As I haven't used matlab too often and don't have the program available now I cannot say for sure, but matlab may be creating a custom environment with custom paths (this happens a lot, so the user has a very consistent experience in their software). When matlab installs it may not export paths to its own modules to your default environment. So when calling for pygame.py outside of matlab, python cannot find pygame.py under its usual lookup paths.
Solutions could be:
find the pygame.py, and map the path to it directly in your code, though this could cause you headaches later on during deployment
Try just copying the pygame.py file to your working directory, could have dependences that need to addressed.
Install pygame directly from its developer at http://www.pygame.org. Version differences could be a problem but pygame gets put under the usual lookup paths for python. (This would be my preferred solution personally.)
Or just export the location of path to pygame in matlab's library to your default enivronment. This could be a problem during deployment too.
For posterity, first try everything that Stewie noted here ("Undefined variable "py" or class" when trying to load Python from MATLAB R2014b?). If it doesnt work then it's possible that you have multiple pythons. You can try and check which python works (with all the related installed modules) on your bash/terminal. And then use
pyversion PYTHONPATH
to let matlab know the right path.
Also use py.importlib.import_module('yourmodule') to import the module after that.
That should get you started.
Related
I am new to Python so this may be a stupid question, sorry in advance if it is so!
The paths Python searches for modules using Spyder 4.1.4.:
[.., 'D:\Users\Martin\Anaconda3\lib\site-packages', ..]
The paths Python searches for when used via command line in windows:
[.., 'D:\Users\Martin\Anaconda3\lib\site-packages', ..]
Thus, both include path to
'D:\Users\Martin\Anaconda3\lib\site-packages'
where I store my cv2 module installed. Yet, Spyder can import cv2 and to my surprise cmd cannot import cv2 with an error No module named 'cv2'. What am I missing please? Can anyone verify if it works for him in command line please? (I changed/edited the question again to cut unneccessary long talk, though the essence stayed the same, in hope someone could answer).
I solved it. If you have a similar problem, you can check if your case is similar to mine and follow the steps.
I use Spyder and everything works fine. However my goal is to use Python via cmd. This could not be done because Python via cmd could not find my modules.
What I did: After typing python in cmd, Python worked and output its version by default. However, I noticed the version was different than version running in Spyder - I had two Python installations (one of which I didn't know about). I found the installation cmd uses by import sys and print(sys.executable). I uninstalled that Python installation.
Now, typing python in cmd does not do anything, it is an unknown command. Then I followed this guide to add my Python installation to Path (using Windows) by:
My Computer > Properties > Advanced System Settings > Environment Variables >
in System variables, I found "Path", clicked Edit, New, then input my Python installation path D:\Users\Martin\Anaconda3 as well as D:\Users\Martin\Anaconda3\Scripts and D:\Users\Martin\Anaconda3\Library\bin. This solved it for me.
I have a Windows machine in which some Python code works, but now needs to work on new machine.
I have installed the same Python version 3.6.5.
First issue was that when I run the code, it can not find a re.py library, which is in fact in Python's Lib folder. So I have added sys.path.append('C:\Python\Lib') and now it can find it.
But now I get the syntax error from that library, where I say import re, that lines throws an error regarding some line in re.py library. If I import getopt, I also get syntax error on some line.
How is that even possible? Syntax error in pythons Lib files which came with installation?
And the thing is that on machine 1 it works, same file contents, same python version. I am under impression that I have wrong in python.exe version for this version of libraries, but I have simply downloaded Windows installer and installed it.
I don't even know what to google for, does someone has any idea? I am importing re in WeblogicAuto.py on line 5.
D:\Jenkins\workspace\weblogic-full-deployment-copy\weblogic-deployment>MainAutoDeployment.py -f DEV -v 2.61.0.12
Initializing WebLogic Scripting Tool (WLST) ...
Welcome to WebLogic Server Administration Scripting Shell
Type help() for help on available commands
Problem invoking WLST - Traceback (innermost last):
File "D:\Jenkins\workspace\weblogic-full-deployment-copy\weblogic-deployment\WeblogicAuto.py", line 5, in ?
File "C:\Python\Lib\re.py", line 247
b"_abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890")
^
SyntaxError: invalid syntax
You are using WLST (WebLogic Scripting Tool).
WLST is very specific distribution of python:
it's jython
it roughly corresponds with python 2.7
And you trying to import libs from your CPython 3.6.5 distribution.
You need to:
remove your sys.path.append that you added earlier
check python libraries in jython library path. Which could be $HOME/.jython or WLST-specific path (look in WebLogic documentation)
OK many thanks to ya all, I've found the solution, it was about Jython libraries. I will try to elaborate a bit if someone stumbles upon this issue.
What I do here is that I deploy java modules to Oracle Weblogic application server. So this answer will also help someone trying to deploy to Weblogic from python.
From the start I was avoiding to install Webloglogic software on a machine from where I do the deploy (and that is a Jenkins slave which runs these python file, simple job).
I noticed that first machine (first Jenkins slave) has Weblogic installed, but I like to keep it minimal :)
What you do need is weblogic.jar and (not sure at this moment) wlfullclient.jar which is generated on Weblogic server (google how if needed or you may already have it).
The thing is that even though I have pure python code, when you call another python code with java weblogic.WLST pythonCode.py, it will be run with jython application! And it needs its libraries in its sys path.
In jython file I've added print(sys.path) then run in on both machines (slaves). I've noticed that path is different on those machines, even though if you type it in command prompt you get the same, but different then when Jenkins runs it.
So instead of looking how to fix those paths and copy files to them, I have created folders where it expects them, and copied them from first machine (easy fix, I may look into it later).
These are the sys.path and files that were needed, present on first machine:
['D:\\Jenkins\\weblogic\\Lib', '__classpath__', 'C:/bea10/wlserver_10.3/server/lib/weblogic.jar', 'C:/bea10/wlserver_10.3/common/wlst/modules/jython-modules.jar/Lib', 'C:/bea10/wlserver_10.3/common/wlst', 'C:/bea10/wlserver_10.3/common/wlst/lib', 'C:/bea10/wlserver_10.3/common/wlst/modules', '.']
This was sys.path on second machine, so I simply copied there:
['D:\\Jenkins\\weblogic\\Lib', '__classpath__', 'D:/Jenkins/server/lib/weblogic.jar', 'D:/Jenkins/common/wlst/modules/jython-modules.jar/Lib', 'D:/Jenkins/common/wlst', 'D:/Jenkins/common/wlst/lib', 'D:/Jenkins/common/wlst/modules', '.']
Note that jython-modules.jar is a file, so /Lib should be from that file if I get how java works.
Feel free to contact me for more details.
I am attempting to put together a simple c++ test project that uses an embedded python 3.2 interpreter. The project builds fine but Py_Initialize raises a fatal error:
Fatal Python error: Py_Initialize: unable to load the file system codec
LookupError: no codec search functions registered: can't find encoding
Minimal code:
#include <Python.h>
int main (int, char**)
{
Py_Initialize ();
Py_Finalize ();
return 0;
}
The OS is 32bit Vista.
The python version used is a python 3.2 debug build, built from sources using VC++ 10.
The python_d.exe file from the same build runs without any problems.
Could someone explain the problem and how to fix it? My own google-fu fails me.
EDIT 1
After going through the python source code I've found that, as the error says, no codec search functions have been registered. Both codec_register and PyCodec_Register are as they should be. It's just that nowhere in the code are any of these functions called.
I don't really know what this means as I still have no idea when and from where these functions should have been called. The code that raises the error is entirely missing from the source of my other python build (3.1.3).
EDIT 2
Answered my own question below.
Check the PYTHONPATH and PYTHONHOME environment variables and make sure they don't point to Python 2.x.
http://bugs.python.org/issue11288
Parts of this have been mentioned before, but in a nutshell this is what worked for my environment where I have multiple Python installs and my global OS environment set-up to point to a different install than the one I attempt to work with when encountering the problem.
Make sure your (local or global) environment is fully set-up to point to the install you aim to work with, e.g. you have two (or more) installs of, let's say a python27 and python33 (sorry these are windows paths but the following should be valid for equivalent UNIX-style paths just as well, please let me know about anything I'm missing here (probably the DLLs path might differ)):
C:\python27_x86
C:\python33_x64
Now, if you intend to work with your python33 install but your global environment is pointing to python27, make sure you update your environment as such (while PATH and PYTHONHOME may be optional (e.g. if you temporarily work in a local shell)):
PATH="C:\python33_x64;%PATH%"
PYTHONPATH="C:\python33_x64\DLLs;C:\python33_x64\Lib;C:\python33_x64\Lib\site-packages"
PYTHONHOME=C:\python33_x64
Note, that you might need/want to append any other library paths to your PYTHONPATH if required by your development environment, but having your DLLs, Lib and site-packages properly set-up is of prime importance.
Hope this helps.
The core reason is quite simple: Python does not find its modules directory, so it can of course not load encodings, too
Python doc on embedding says "Py_Initialize() calculates the module search path based upon its best guess" ... "In particular, it looks for a directory named lib/pythonX.Y"
Yet, if the modules are installed in (just) lib - relative to the python binary - above guess is wrong.
Although docs says that PYTHONHOME and PYTHONPATH are regarded, we observed that this was not the case; their actual presence or content was completely irrelevant.
The only thing that had an effect was a call to Py_SetPath() with e.g. [path-to]\lib as argument before Py_Initialize().
Sure this is only an option for an embedding scenario where one has direct access and control over the code; with a ready-made solution, special steps may be necessary to solve the issue.
Ran into the same thing trying to install brew's python3 under Mac OS! The issue here is that in Mac OS, homebrew puts the "real" python a whole layer deeper than you think. You would think from the homebrew output that
$ echo $PYTHONHOME
/usr/local/Cellar/python3/3.6.2/
$ echo $PYTHONPATH
/usr/local/Cellar/python3/3.6.2/bin
would be correct, but invoking $PYTHONPATH/python3 immediately crashes with the abort 6 "can't find encodings." This is because although that $PYTHONHOME looks like a complete installation, having a bin, lib etc, it is NOT the actual Python, which is in a Mac OS "Framework". Do this:
PYTHONHOME=/usr/local/Cellar/python3/3.x.y/Frameworks/Python.framework/Versions/3.x
PYTHONPATH=$PYTHONHOME/bin
(substituting version numbers as appropriate) and it will work fine.
From python3k, the startup need the encodings module, which can be found in PYTHONHOME\Lib directory.
In fact, the API Py_Initialize () do the init and import the encodings module.
Make sure PYTHONHOME\Lib is in sys.path and check the encodings module is there.
I had this issue with python 3.5, anaconda 3, windows 7 32 bit. I solved it by moving my pythonX.lib and pythonX.dll files into my working directory and calling
Py_SetPythonHome(L"C:\\Path\\To\\My\\Python\\Installation");
before initialize so that it could find the headers that it needed, where my path was to "...\Anaconda3\". The extra step of calling Py_SetPythonHome was required for me or else I'd end up getting other strange errors where python import files.
I just ran into the exact same problem (same Python version, OS, code, etc).
You just have to copy Python's Lib/ directory in your program's working directory ( on VC it's the directory where the .vcproj is )
There appears to be something going wrong with the release build either failing to include the appropriate codecs or else misidentifying the codec to use for system APIs. Since the python_d executable is working, what does that return for os.getfsencoding()? (Use the C API to call that between your Initialize/Finalize calls)
I had the same issue and found this question. However from the answers here I was not able to solve my problem. I started debugging the cpython code and thought that I might be discovered a bug. Therefore I opened a issue on the python issue tracker.
My mistake was that I did not understand that Py_SetPath clears all inferred paths.
So one needs to set all paths when calling this function.
Link to the issue conversation
For completion I also copied the most important part of the conversation below.
My original issue text
I compiled the source of CPython 3.7.3 myself on Windows with Visual Studio 2017 together with some packages like e.g numpy. When I start the Python Interpreter I am able to import and use numpy. However when I am running the same script via the C-API I get an ModuleNotFoundError.
So the first thing I did, was to check if numpy is in my site-packages directory and indeed there is a folder named numpy-1.16.2-py3.7-win-amd64.egg. (Makes sense because the python interpreter can find numpy)
The next thing I did was to get some information about the sys.path variable created when running the script via the C-API.
#### sys.path content ####
C:\Work\build\product\python37.zip
C:\Work\build\product\DLLs
C:\Work\build\product\lib
C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO\2017\PROFESSIONAL\COMMON7\IDE\EXTENSIONS\TESTPLATFORM
C:\Users\rvq\AppData\Roaming\Python\Python37\site-packages
Examining the content of sys.path I noticed two things.
C:\Work\build\product\python37.zip has the correct path 'C:\Work\build\product\'. There was just no zip file. All my files and directory were unpacked. So I zipped the files to an archive named python37.zip and this resolved the import error.
C:\Users\rvq\AppData\Roaming\Python\Python37\site-packages is wrong it should be C:\Work\build\product\Lib\site-packages but I dont know how this wrong path is created.
The next thing I tried was to use Py_SetPath(L"C:/Work/build/product/Lib/site-packages") before calling Py_Initialize(). This led to
Fatal Python Error 'unable to load the file system encoding'
ModuleNotFoundError: No module named 'encodings'
I created a minimal c++ project with exact these two calls and started to debug Cpython.
int main()
{
Py_SetPath(L"C:/Work/build/product/Lib/site-packages");
Py_Initialize();
}
I tracked the call of Py_Initialize() down to the call of
static int
zipimport_zipimporter___init___impl(ZipImporter *self, PyObject *path)
inside of zipimport.c
The comment above this function states the following:
Create a new zipimporter instance. 'archivepath' must be a path-like
object to a zipfile, or to a specific path inside a zipfile. For
example, it can be '/tmp/myimport.zip', or
'/tmp/myimport.zip/mydirectory', if mydirectory is a valid directory
inside the archive. 'ZipImportError' is raised if 'archivepath'
doesn't point to a valid Zip archive. The 'archive' attribute of the
zipimporter object contains the name of the zipfile targeted.
So for me it seems that the C-API expects the path set with Py_SetPath to be a path to a zipfile. Is this expected behaviour or is it a bug?
If it is not a bug is there a way to changes this so that it can also detect directories?
PS: The ModuleNotFoundError did not occur for me when using Python 3.5.2+, which was the version I used in my project before. I also checked if I had set any PYTHONHOME or PYTHONPATH environment variables but I did not see one of them on my system.
Answer
This is probably a documentation failure more than anything else. We're in the middle of redesigning initialization though, so it's good timing to contribute this feedback.
The short answer is that you need to make sure Python can find the Lib/encodings directory, typically by putting the standard library in sys.path. Py_SetPath clears all inferred paths, so you need to specify all the places Python should look. (The rules for where Python looks automatically are complicated and vary by platform, which is something I'm keen to fix.)
Paths that don't exist are okay, and that's the zip file. You can choose to put the stdlib into a zip, and it will be found automatically if you name it the default path, but you can also leave it unzipped and reference the directory.
A full walk through on embedding is more than I'm prepared to type on my phone. Hopefully that's enough to get you going for now.
I had the problem and was tinkering with different solutions mentioned here. Since I was running my project from Visual Studio, apparently, I needed to set the environment path inside Visual Studio and not the system path.
Adding a simple PYTHONHOME=PATH\TO\PYTHON\DIR in the project solution\properties\environment solved the problem.
For me this happened when I updated Python 64 bit from 3.6.4 to 3.6.5. It threw some error like "unable to extract python.dll. Do you have permissions."
Pycharm also failed to load interpreter, even though I reloaded it in settings. Running python command gave same error, with and without administrator mode.
Reason
There was error in installation of Python, include folder in python installation directory C:\Users\USERNAME\AppData\Local\Programs\Python\Python36 was missing
Reinstalling Python also dint solve the issue.(Not removal and install)
Solution
Uninstall Python and Install of Python again.
Because running installer was just extracting same files excluding include folder
In my cases, for windows, if you have multiple python versions installed, if PYTHONPATH is pointing to one version the other ones didn't work. I found that if you just remove PYTHONPATH, they all work fine
For those working in Visual Studio simply add the include, Lib and libs directories to the Include Directories and Library Directories under
Projects Properties -> Configuration Properties > VC++ Directories :
For example I have Anaconda3 on my system and working with Visual Studio 2015 This is how the settings looks like (note the Include and Library directories) :
Edit:
As also pointed out by bossi setting PYTHONPATH in your user Environment Variables section seems necessary.
a sample input can be like this (in my case):
C:\Users\Master\Anaconda3\Lib;C:\Users\Master\Anaconda3\libs;C:\Users\Master\Anaconda3\Lib\site-packages;C:\Users\Master\Anaconda3\DLLs
is necessary it seems.
Also, you need to restart Visual Studio after you set up the PYTHONPATH in your user Environment Variables for the changes to take effect.
Also note that :
Make sure the PYTHONHOME environment variable is set to the Python
interpreter you want to use. The C++ projects in Visual Studio rely on
this variable to locate files such as python.h, which are used when
creating a Python extension.
So, for some reason the python dll fails to locate the encodings module. The python.exe executable apparently finds it because it has the expected relative path. Modifying the search path works.
The reason for all of this? Don't know but at least it works. I highly suspect a typo on my part somewhere, that's usually the reason for odd bugs it seems.
There is a bunch of pre-made code I simply have to run. However, the code requires the module NumPy, which for some reason is not installed. I am using Geany for the Python code, and when I click compile, the console states:
"Traceback (most recent call last):
File "chi2Fit.py", line 1, in <module>
import numpy as np
ImportError: No module named 'numpy'
I really tried to look it up, and I found the zipped NumPy packages on SourceForge, but I cannot install them. I am using Windows 10 (Virtual Machine is buggy, unfortunately). I usually run my Python programs by compiling them directly and don't use the commands within the console (so honestly I don't know how to open the command line. Yes, I am a beginner). What is the explanation?
Geany is just an editor, with the ability to run commands and such from menus and buttons. So you should be able to run this code 'by compiling them directly'. If that works while the 'geany compile' does not, then you need to check the 'compile' command. Is it using the right Python?
'compile' really doesn't make sense with Python code. You are just executing a script.
NumPy is a large package that does include compiled components. So installing it requires more than downloading a ZIP file. On Windows it is usually best to install one of the precompiled packages. Anaconda is popular one.
But we know nothing about this pre-made code, and whether it has included the necessary modules or not. You need to find out from the source of that code what is needed to run it.
You need to figure out how to install NumPy. It depends on what OS you are using.
There are pre-compiled packages for Windows. There is plenty of information here on SO (e.g., Installing NumPy on Windows) or you can use Google.
This is the first time I have attempted to use anything other than what's provided by python.
I have recently gotten into pythons provided Tkinter, though due to some issues I decided to use another GUI, and heard that PyQt was highly recommended, so I downloaded that and looked into various tutorials. In these tutorials, I cannot seem to execute any of the import statements in said tutorials that relate to PyQt, primarily PyQt5 (I have checked I have the correct version number by the way).
So for instance:
import PyQt5
raises the error:
Traceback (most recent call last):
File "/Users/MEBO/PycharmProjects/Music/testing.py", line 1, in <module>
import Qt
ImportError: No module named 'Qt'
[Finished in 0.1s with exit code 1]
I have a lot of research into this. I've heard people talk of using pip to install modules, and I have done this be safe (as well as downloading it from the internet), I've tried changing the project interpreter to versions Python3/ 2.7/ 2.6, appending the path name to the sys.path directory, (which I really know nothing about to be honest, I was hoping I'd get lucky), though nothing seems to work.
Are you supposed to be able to just import a module off the bat, or do you have to set some things up first?
For windows download the package and extract it to (path where python installed)\Python27\Lib and then try to import.
Specific to PyQt
This package cannot just be downloaded and imported, it must be built because it is not pure python, it uses Qt (C++) and requires dependancies. Read this tutorial on installation.
There is also a very complete python package distribution, Anaconda, that includes pyqt and much more. Almost all the packages I ever looked at are in there.
In general to pure python code
In other cases, if you place modules/code that has been download into the directory that your python script is run from, you can import off the bat, or you can append/insert any folder to the sys.path.
# importer will search here last
sys.path.append('/path/to/code/')
# importer will search here second, right after script's directory
# this can be useful to override a module temporarily...
sys.path.insert(1,'/path/to/code/')