I tried to install mypy with "phyton -m pip install mypy" but it fails with an error about typed_ast that says it needs Visual C++ compiler but after installing that the error remains. I found several similar reports and notes that it can't be fixed due to the typed_ast thing, I don't know any details about that.
Is there a way to install mypy manually? Just copy a bunch of files somewhere?
I use Windows 10, Python 3.7, I updated to the latest pip.
Any help or hint is welcome
Thanks a lot
Martin
I found an answer myself.
I have python 3.7-32 installed and there is no appropriate wheel for typed -ast for this. This video
https://www.youtube.com/watch?v=XZrThBBpFlo
explains the problem and also gives a solution. I installed a 32-bit wheel from the link given and then installed mypy again and it finished successfully.
Now I will try mypy.
Good luck
My Mac came installed with python 2.7 as the default python version. But, this version is no longer supported by many packages and software. I searched several online forums regarding how to change the default python version on mac. But, none of them seem to work. I also installed the latest version of python, and if I type:
python --version
It returns the version as python 3.8. But if I try to install packages like Biopython, I get an error like this -
defaulting to user installation because normal site-packages is not
writeable
Collecting biopython Using cached biopython-1.77.tar.gz (16.8 MB)
ERROR: Command errored out with exit status 1:
Biopython requires Python 3.6 or later. Python 2.7 detected
I am really finding it difficult to install many packages required for my work. Any help or suggestions would be greatly appreciated.
Thank you.
Probably, you just have to change your Python symbolic link.
Please check this, and you will get it: https://dev.to/malwarebo/how-to-set-python3-as-a-default-python-version-on-mac-4jjf
After trying to continuously trying to install and run scrapy, i have hit a wall and cannot figure out what else to do.
upon initialising venv within folder with python 3.6.12,
scrapy startproject scraperproj
i am presented with the following error
`ImportError: dlopen(/Users/adris/Desktop/webscraper/venv/lib/python3.6/site-packages/_cffi_backend.cpython-36m-darwin.so, 2): Library not loaded: /usr/local/opt/libffi/lib/libffi.7.dylib
Referenced from: /Users/adris/Desktop/webscraper/venv/lib/python3.6/site-packages/_cffi_backend.cpython-36m-darwin.so
Reason: Incompatible library version: _cffi_backend.cpython-36m-darwin.so requires version 9.0.0 or later, but libffi.7.dylib provides version 1.0.0`
after 8 hours of continuous efforts, i tried myself at pip installing via using pip3 seemed to do the job! all working now
I have just installed pycharm 2019 edition. I have already installed python 3.7 in my system. My normal python program in pycharm is running fine i.e. printing hello world but I am not able to install packages like pandas and all. its showing error. 2nd thing i am not able to see latest version of pip that is been shown in pycharm.
I have tried to do this with some changes in manage repositories but It didn't wokred
While clicking on pip its showing "Error loading package list:pypi.python.org" this error message.
I want to install packages but cant able to do it.
Please download Anaconda Distribution, which is basically made for pandas and all. You can use Spyder which is one of the best tools for Data Science. There you can easily install pandas.
I'm having an error running simple code using cv2 module.
It's just:
import cv2
img = cv2.imread('sudoku.png',0)
cv2.imshow('image',img)
And it fails with the following error:
QObject::moveToThread: Current thread (0x1b74720) is not the object's thread (0x1e57d70).
Cannot move to target thread (0x1b74720)
I googled this error and tried a lot of things but it doesn't help. I tried installing without pip, I tried using step-by-step installation (from official OpenCV) but nothing helps.
When I run:
cv2.__version__
It returns 3.4.3
As noted already, the basis for this problem is discussed in opencv-python issue 46, and results from the duplication of the following libraries both on the host and the opencv-python distro libQtDBus libQtCore and libQtGui.
It has been lately addressed in the newest release of opencv-python. It is not a fix to the source code, rather the fix is to force pip to compile the newly available source via
pip install --no-binary opencv-python opencv-python
This will cause opencv-python to use the same libraries as the host, so the conflict no longer exists.
According to this issue posted on the OpenCV GitHub, this is a known issue that the developer states is damn near impossible to fix. It is apparently caused by a conflict in any Qt installations on the system with the Qt that is shipped with OpenCV. There are some suggestions floating around to remove the libqt5x11extras5 package from the system. This may fix it for some but anyone running these libraries on a Linux distribution that uses a window manager based on Qt will render their desktop environment unusable by removing this package (having tried it myself).
You can try building OpenCV from source using the WITH_GTK=ON option when running cmake which will use GTK instead of Qt, circumventing the conflict. However, this is hard to make use of in Python when using virtual environments.
I haven't spent the time to fully appreciate this problem, but as I understand this is caused by multiple conflicting versions of some plugin in the environment. I tried installing building opencv-python but there were errors with that approach. Another suggestion is to change your import order, but I've had mixed success with that, and I couldn't get it to work on a project today.
But I found a workaround that worked for me. Install opencv-python-headless instead of opencv-python. This will avoid installing the conflicting plugins. It may not work for you depending on what features of opencv you need.
$ pip uninstall opencv-python
$ pip install opencv-python-headless
The error was fixed on my system, by simply updating one library.
To find out where it is coming from, assuming Linux, try the following,
LD_DEBUG=files python -c "import cv2"
or,
LD_DEBUG=files python -c "import cv2 ; img = cv2.imread('myimage.png',0) ; cv2.imshow('image',img) ; cv2.waitKey(0)"
On my machine, it failed in one of the blas libraries. I updated that library and the code now runs without error.
This is an old bug you can find it discussed in a number of online communities.
My test code is as follows. Notably the error has not reoccurred, and apparently has nothing to do with Qt.
import cv2
img = cv2.imread('sudoku.png',0)
cv2.imshow('image',img)
cv2.waitKey(0)
To me, the solution to this problem was removing Anaconda, then installing pip followed by installing OpenCV with a simple pip install command.