Autocomplete in PyCharm for Python compiled extensions
Question:
When writing Python code using compiled extensions (the OpenCV Python bindings, for example), PyCharm doesn’t seem to be aware of their availability. The imports are marked with a grey underline, saying “unresolved reference” as a tooltip, and autocomplete doesn’t work, either. (Except for the function names already used in the code.)
This isn’t caused by wrong module paths, the code runs without error when started. Also, after I import the modules in a Python shell, autocomplete starts working as expected.
Is there a solution for that or is this an architectural limitation for compiled extensions? Are there any other IDEs that manage to cope with this problem?
Answers:
I hate to give a “works for me” answer, but maybe the details on my environment will help you identify the problem on your end.
I’ve never used PyCharm before, but I just did a test on Mac 10.6.6 using PyCharm 1.1.1, with Macports opencv +python26. The autocomplete worked fine for me the first time. I also closed and re-ran PyCharm and was able to autocomplete without doing anything further. I also had no issue with autocomplete for other native extensions I tried like cjson, procname.
.
Perhaps it is a platform-specific issue (Windows?), or a bug affecting an older version of PyCharm?
The imports are marked with a grey underline, saying “unresolved reference” as a tooltip
This most probably means that PyCharm can’t see the module you import. In editing mode, PyCharm relies on availability of Python sources of imported modules. If a module is not written in Python but is a C extension module, PyCharm generates a ‘skeleton’ that contains function prototypes, and uses it for completion.
In shell mode, PyCharm uses live imported objects for completion, with slightly different results.
Make sure that your OpenCV installation is visible for the Python interpreter you chose for the project (File / Settings / Python interpreter). If the interpreter is correct, try removing and re-adding it (this is time-consuming a bit, sorry).
If nothing helps, file a bug.
PyCharm currently does not scan compiled extensions/binaries which are in a path manually added to the interpreter in the IDE. I have filed a bug with Jetbrains in YouTrack. You might want to have a look at it and possibly the discussion I initiated in their discussion forum (link is in the bug description). I’d appreciate if you could vote for this issue to be resolved in YouTrack if you are a PyCharm user facing the same problem.
Try clicking “Reload” button in File | Settings | IDE Settings | Python interpreters. That got it working for me.
In my case on OS X 10.8 and PyCharm 3, IDE was automatically picking different installations of Python. I noticed this in Eclipse Pydev, which picked up the one right one and worked as expected. It was not easy to notice the difference between the two:
/System/Library/Frameworks/Python.framework/Versions/2.7/bin/python
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/python
I follow the instructions under this question:
How to install OpenCV on Windows and enable it for PyCharm without using the package manager
After that it does not work and I reinstall the pycharm ide without any other changes and now it is working perfectly.
I know that this is not the best answer, but after a lot of time wasted and trying different workarounds this was the one that solve my problem, I hope it can help you.
I have noticed a difference in pycharm behavior depending on the way to import.
using:
import cv2
the auto completion doesn’t work,
while with:
from cv2 import cv2
auto completion works
I had to hardlink the binary into the folder lib-dynload of my interpreter.
$ cd /usr/lib/python3.7/lib-dynload
$ sudo ln /usr/local/lib/python3.7/dist-packages/cv2/python-3.7/cv2.cpython-37m-x86_64-linux-gnu.so cv2.cpython-37m-x86_64-linux-gnu.so
The paths may vary in your environment. I didn’t test it on OSX or Windows, but it may work there too. The lib-dynload folder is here:
After two days test,I finally fix this issue:
The difference:
- Uninstall python 3.7.2,install python 3.7.7.
- Change the path where python install.(I strongly doubt that the cause is that my PATH of
opencv-python has some Chinese characters.It should have only English).
Then do:
- Install the
opencv-contrib-python.
In my case, include opencv in the path install-opencv-4-on-windows. and add it to the project settings, if none of this works for you, I recommend that you install anaconda change the python interpreter and use the anaconda interpreter.
for this go to : file -> settings -> project:test -> python interpreter and select conda interpreter
if you dont have anaconda you can download at https://www.anaconda.com/
follow the steps in the link python-opencv to install opencv in anaconda
When writing Python code using compiled extensions (the OpenCV Python bindings, for example), PyCharm doesn’t seem to be aware of their availability. The imports are marked with a grey underline, saying “unresolved reference” as a tooltip, and autocomplete doesn’t work, either. (Except for the function names already used in the code.)
This isn’t caused by wrong module paths, the code runs without error when started. Also, after I import the modules in a Python shell, autocomplete starts working as expected.
Is there a solution for that or is this an architectural limitation for compiled extensions? Are there any other IDEs that manage to cope with this problem?
I hate to give a “works for me” answer, but maybe the details on my environment will help you identify the problem on your end.
I’ve never used PyCharm before, but I just did a test on Mac 10.6.6 using PyCharm 1.1.1, with Macports opencv +python26. The autocomplete worked fine for me the first time. I also closed and re-ran PyCharm and was able to autocomplete without doing anything further. I also had no issue with autocomplete for other native extensions I tried like cjson, procname.
.
Perhaps it is a platform-specific issue (Windows?), or a bug affecting an older version of PyCharm?
The imports are marked with a grey underline, saying “unresolved reference” as a tooltip
This most probably means that PyCharm can’t see the module you import. In editing mode, PyCharm relies on availability of Python sources of imported modules. If a module is not written in Python but is a C extension module, PyCharm generates a ‘skeleton’ that contains function prototypes, and uses it for completion.
In shell mode, PyCharm uses live imported objects for completion, with slightly different results.
Make sure that your OpenCV installation is visible for the Python interpreter you chose for the project (File / Settings / Python interpreter). If the interpreter is correct, try removing and re-adding it (this is time-consuming a bit, sorry).
If nothing helps, file a bug.
PyCharm currently does not scan compiled extensions/binaries which are in a path manually added to the interpreter in the IDE. I have filed a bug with Jetbrains in YouTrack. You might want to have a look at it and possibly the discussion I initiated in their discussion forum (link is in the bug description). I’d appreciate if you could vote for this issue to be resolved in YouTrack if you are a PyCharm user facing the same problem.
Try clicking “Reload” button in File | Settings | IDE Settings | Python interpreters. That got it working for me.
In my case on OS X 10.8 and PyCharm 3, IDE was automatically picking different installations of Python. I noticed this in Eclipse Pydev, which picked up the one right one and worked as expected. It was not easy to notice the difference between the two:
/System/Library/Frameworks/Python.framework/Versions/2.7/bin/python
/opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/python
I follow the instructions under this question:
How to install OpenCV on Windows and enable it for PyCharm without using the package manager
After that it does not work and I reinstall the pycharm ide without any other changes and now it is working perfectly.
I know that this is not the best answer, but after a lot of time wasted and trying different workarounds this was the one that solve my problem, I hope it can help you.
I have noticed a difference in pycharm behavior depending on the way to import.
using:
import cv2
the auto completion doesn’t work,
while with:
from cv2 import cv2
auto completion works
I had to hardlink the binary into the folder lib-dynload of my interpreter.
$ cd /usr/lib/python3.7/lib-dynload
$ sudo ln /usr/local/lib/python3.7/dist-packages/cv2/python-3.7/cv2.cpython-37m-x86_64-linux-gnu.so cv2.cpython-37m-x86_64-linux-gnu.so
The paths may vary in your environment. I didn’t test it on OSX or Windows, but it may work there too. The lib-dynload folder is here:
After two days test,I finally fix this issue:
The difference:
- Uninstall python 3.7.2,install python 3.7.7.
- Change the path where python install.(I strongly doubt that the cause is that my PATH of
opencv-pythonhas some Chinese characters.It should have only English).
Then do:
- Install the
opencv-contrib-python.
In my case, include opencv in the path install-opencv-4-on-windows. and add it to the project settings, if none of this works for you, I recommend that you install anaconda change the python interpreter and use the anaconda interpreter.
for this go to : file -> settings -> project:test -> python interpreter and select conda interpreter
if you dont have anaconda you can download at https://www.anaconda.com/
follow the steps in the link python-opencv to install opencv in anaconda