I'm trying to use pyFirmata, but I can't get it to work. Even the most basic of the library does not work. I guess there is something wrong with the library code.
from pyfirmata import Arduino,util
import time
port = 'COM5'
board = Arduino(port)
I get this error:
Traceback (most recent call last):
File "c:\Users\Public\pythonpublic\arduino.py", line 5, in <module>
board = Arduino(port)
^^^^^^^^^^^^^
File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\__init__.py", line 19, in __init__
super(Arduino, self).__init__(*args, **kwargs)
File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 101, in __init__
self.setup_layout(layout)
File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 157, in setup_layout
self._set_default_handlers()
File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 161, in _set_default_handlers
self.add_cmd_handler(ANALOG_MESSAGE, self._handle_analog_message)
File "C:\Users\marce\AppData\Roaming\Python\Python311\site-packages\pyfirmata\pyfirmata.py", line 185, in add_cmd_handler
len_args = len(inspect.getargspec(func)[0])
^^^^^^^^^^^^^^^^^^
AttributeError: module 'inspect' has no attribute 'getargspec'. Did you mean: 'getargs'?
As already pointed out in another answer, the pyFirmata modules is currently documented to run on Python 2.7, 3.6 and 3.7. This doesn't mean it won't work on other versions, but probably that it hasn't been tested on other versions by the author and it isn't officially supported. So it may or may not work on newer Python versions.
Your error message is caused by a missing function inspect.getargspec(). This function is part of the Python Standard Library, but has been deprecated since Python 3.0 (which came out in 2008). Unfortunately the author wasn't aware of this or simply didn't bother to fix it, so now the code doesn't work anymore with the latest version of Python.
In the Python documentation, you can see that the function is still available in version 3.10, but not in version 3.11.
To solve this you have a number of options:
Downgrade to Python 3.10, which is currently still a good option (Python 3.10 is "alive" until 2026-10-04). I don't know if all other functionality does work. I guess it will, but you would have to find out yourself.
Downgrade to Python 3.7, which is claimed to be supported. Given that Python 3.7 is also still alive (until 2023-06-27), that's a reasonable option as well.
Create an issue for the pyFirmata module and hope the author will fix the problem. Note that an issue has already been created by someone in 2019 but apparently without effect. You could leave a comment there confirming that this has now broken for real.
Clone the library and fix it yourself (and create a Pull Request to get it in the official library).
Find another, similar, library that does work with Python 3.11.
Write the code yourself.
Downgrading to a Python version between 3.7 and 3.10 is certainly the simplest option, and leaving some feedback to the author will give you a chance it will be fixed in the future, in case your planning to use your script for a longer time.
According to the first line of pyFirmata docs:
It runs on Python 2.7, 3.6 and 3.7
You are using Python 3.11. The inspect (core library module) has changed since Python 3.7.
Related
I am attempting to use the PyMultinest package. The full error text I am encountering is AttributeError:dlsym(RTLD_DEFAULT, run): symbol not found in the __getitem__() function in ctypes/__init__.py. I'll include more text and code below, but I am mostly trying to understand what this error is telling me - my Google Fu is apparently lacking, and the StackExchange questions I have seen relating to this error seem to be hyper-focused on solving a specific instance of this error. So - What is this error trying to tell me is wrong?
More context. I attempt to execute the PyMultinest (PMN) package as directed in the PMN documentation. PMN is, effectively, a Python wrapper for a C program. Running PMN requires a fair bit of setup code (several ancillary functions need to be defined, as well as a host of variables), which I'm not including here by default because it's ... a lot, but I can if needed. The PMN execution line I use is
pmn.run(Loglike, Prior, ndims, n_live_points=1000, n_params=n_params, outputfiles_basename='./'+ProjectName+'/temp_', resume=False, verbose=True)
This returns the error traceback
File "[redacted]", line 139, in <module>
pmn.run(Loglike, Prior, ndims, n_live_points=1000, n_params=n_params, outputfiles_basename='./'+ProjectName+'/temp_', resume=False, verbose=True)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/pymultinest/run.py", line 254, in run
lib.run(*args_converted)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 386, in __getattr__
func = self.__getitem__(name)
File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/ctypes/__init__.py", line 386, in __getitem__
func = self._FuncPtr((name_or_ordinal, self))
AttributeError: dlsym(RTLD_DEFAULT, run): symbol not found
If it helps, I have determined that the name variable being passeed through self.__getitem__(), and thus into self._FuncPtr(), is run. Although, that might be obvious looking at the AttributeError message.
I am running Python 3.8 (as shown above) on a MacOS machine. Last summer, I was able to execute PMN on this machine using extremely similar code to that which I am using now. I am currently trying to optimize my code from last summer, which is why I'm surprised it isn't simply "working".
So far my attempts at fixing this have been mostly centered on reinstalling PMN. I have done a clean install (pip uninstall/pip install) of the PMN package, as well as following the PMN documentation to rebuild the C portion of the package. I have included the source directories of the C software in my Path variables - or at least, I tried to, I am assuming I was successful, but I'm not very familiar with Macs.
Ultimately, I just wish I understood what Python was telling me with this error better. It would help me direct my own attempts at solving the issue. I suspect it is saying "We don't know where to find this 'run' command you're asking for," in which case I need to figure out why my Path variable changes aren't working. Am I on the right path?
Some hints how to resolve this are given in these issues:
https://github.com/JohannesBuchner/PyMultiNest/issues/160
https://github.com/JohannesBuchner/PyMultiNest/issues/163
It is important to cleanly recompile (empty build folder) when the environment changes, so that cmake recognises changed libraries and compilers.
Check if you are running everything with python3 and not python (works as python 2.x is you have both version 2 and 3 installed)
Check is all the PyMultiNest python files are rewritten in python 3 style, e.g. $ print "something" becomes $ print("something")
My supervisor was accidentally running on python 2.7 and got the same error, so your error might as well be due to mismatch of python version usages.
Run command flutter pub cache clean and flutter clean and after that run flutter pub get now relaunch your emulator it worked for me.
I had tested a web based application which uses Python (2.7.8) scripts to create a dynamic content.
I am parsing some XML data and performing several operations on it.
One of the operations requires searching certain type of data which uses the findall(xpath) function from ElementTree.
Now the place where I need to deploy is a Linux box which has an older version of Python (2.6.6).
I had some trouble due to the older ElementTree not having certain capabilities.
I followed this ElementTree SyntaxError: expected path separator ([). I copied the ElementTree from 2.7.8 to the new box and imported from there.
It imports fine but now I get a different error which is as follows:
Traceback (most recent call last):
File "./filename_python.py", line 117, in <module>
for ch in child.findall(xpath):
File "/usr/lib64/python2.6/xml/etree/ElementPath.py", line 293, in findall
return list(iterfind(elem, path, namespaces))
File "/usr/lib64/python2.6/xml/etree/ElementPath.py", line 194, in select
if "".join(e.itertext()) == value:
AttributeError: itertext
I cannot update the Python version on that box and I cannot add any modules so anything new has to be imported locally.
Any help is appreciated.
Thank you.
It doesn't seem to me that you've backported the 2.7.x version library properly. Take a look at the stack trace and you will see it is still referring to the library in your Python 2.6.x path:
/usr/lib64/python2.6/xml/etree/ElementPath.py
You could also consider lxml - you don't need to install it as a system library. Simply clone from the git repository here, and copy the code into your projects directory.
I am trying to use NetworkX 1.8.1 with Ironpython 2.7. Now I've been stuck to this problem for about 12 hours so far.... but without any luck. Whenever I tried to import networkX, I am having 'non implemented' error as below:
NotImplementedError: The method or operation is not implemented. File
"C:\Program Files (x86)\IronPython
2.7\lib\site-packages\networkx\algorithms\isomorphism\matchhelpers.py",
line 23, in copyfunc return types.FunctionType(f.func_code,
f.func_globals, name or f.name, .....
I tested networkx 1.6, but the same result. It seems that there are some problems in line 23 of matchhelpers.py, but I could never figured it out. Can anyone look into this problem? I am so desperate.....
(And also please recommend me any alternative Graph libraries compatible with IronPython)
Thanks!
This appears to be a bug in IronPython - types.FunctionType resolves to a constructor call that throws a NotImplementedException (see https://github.com/IronLanguages/main/blob/master/Languages/IronPython/IronPython/Runtime/PythonFunction.cs#L72).
It's old code, so I'm not sure why it does that. I've opened issue #35180 to track it.
I have Blender 2.66a which is an application that offers Python 3.3 APIs, On my system I have an installation of Python 3.2 with several modules that I wish to use inside Blender, I tried both
sys.path.append(r"/usr/lib/python3.2/")
sys.path.append("/usr/lib/python3.2/")
and this commands gives no errors, infact even the autocomplete feature works and new modules are indexed, so i tried
import tkinter
but this generates the following error
Traceback (most recent call last):
File "<blender_console>", line 1, in <module>
File "/usr/lib/python3.2/tkinter/__init__.py", line 42, in <module>
raise ImportError(str(msg) + ', please install the python-tk package')
ImportError: No module named '_tkinter', please install the python-tk package
and I don't get the point of this error because it fails to load a module that it's there asking me to install the same module because that module is not installed ( ? ).
What can cause this obscure problem ?
EDIT
the tkinter module works from the gnome-terminal
If I got you right, you're using Python 3.3 from Blender but try to include the 3.2 standard library. This is bound to give you a flurry of issues, you should not do that. Find another way. It's likely that Blender offers a way to use the 3.3 standard library (and that's 99% compatible with 3.2). Pure-Python third party library can, of course, be included by fiddling with sys.path.
The specific issue you're seeing now is likely caused by the version difference. As people have pointed out in the comments, Python 3.3 doesn't find the _tkinter extension module. Although it is present (as it works from Python 3.2), it is most likely in a .so file with an ABI tag that is incompatible with Blender's Python 3.3, hence it won't even look at it (much like a module.txt is not considered for import module). This is a good thing. Extension modules are highly version-specific, slight ABI mismatches (such as between 3.2 and 3.3, or two 3.3 compiled with different options) can cause pretty much any kind of error, from crashes to memory leaks to silent data corruption or even something completely different.
You can verify whether this is the case via import _tkinter; print(_tkinter.__file__) in the 3.2 shell. Alternatively, _tkinter may live in a different directory entirely. Adding that directory won't actually fix the real issue outlined above.
I am playing around with entangled which makes use of os.spawnlp. I am currently running Python 2.7.2.
Here's the error I am getting.
Traceback (most recent call last): File "create_network.py", line
47, in
nodes.append(os.spawnlp(os.P_NOWAIT, 'python', 'python py', str(startPort))) AttributeError: 'module' object has no attribute
'spawnlp'
How do I go about solving this issue? There doesn't seem to be any indication that spawnlp was removed/deleted since it was first added in version 1.6.
I've already re-downloaded the windows python installer and ran it with the repair option. The only thing I can think it might be is that this computer is 64bit and the python version is 32bit... I don't think that's the problem but that's the only thing I can think of...
Lastly, its recommended to use the subprocess module rather than the os.spawn*
In the python documentation it states that
spawnlp(), spawnlpe(), spawnvp() and spawnvpe() are not available on Windows. spawnle() and spawnve() are not thread-safe on Windows; we advise you to use the subprocess module instead
You have to indeed use another module to create subprocesses.