ImportError: No module named 'Cython'

Question

I'm trying do from Cython.Build import cythonize and I get the message ImportError: No module named 'Cython', but I instaled the Cython with the comand pip install Cython. What's wrong?

Python 3.5 Cython 0.25.2 Windows 8

What is the output of running `python --version` in your terminal? — Brian, May 15 '17 at 15:07
If you have multiple python-versions, the most robust way, is to use `python -m pip xxxx`, as described in the duplicate. — ead, Nov 06 '20 at 11:12

score 55 · Answer 1 · answered Jun 25 '19 at 03:18

55

just directly install from pypi: pip install Cython
https://pypi.org/project/Cython/

answered Jun 25 '19 at 03:18

Xiaoyu Xu

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score 30 · Answer 2 · edited Jan 28 '21 at 15:28

30

Use Pip3 command:

pip3 install --upgrade cython

edited Jan 28 '21 at 15:28

DavidW

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answered Dec 22 '19 at 22:38

baraa yusri

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I've undone an edit that changed `pip3` -> `pip` since it seems to change the point of this answer. The useful bit of the edit was to suggest (that on some shells) `alias pip=pip3` (for those that want to only type `pip`). – DavidW Jan 28 '21 at 15:48

score 8 · Accepted Answer · edited Jun 29 '18 at 14:13

8

I reinstalled the Cython with conda and install the Microsoft Visual C++ Build Tools and it works fine.

edited Jun 29 '18 at 14:13

Jeru Luke

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answered Jun 06 '17 at 22:30

Tais

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score 5 · Answer 4 · edited Sep 20 '18 at 10:55

5

You can download the the newest Cython release from http://cython.org/ or you can directly download by clicking this link here Unpack the tarball or zip file, enter the directory, and then run:

python setup.py install

edited Sep 20 '18 at 10:55

JohannesB

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answered Mar 24 '18 at 21:01

Pranav balu

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score 3 · Answer 5 · answered Oct 21 '21 at 11:24

3

The problem for me was the pip version. Running python -m pip install pip --upgrade solved the issue.

answered Oct 21 '21 at 11:24

Charalamm

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score 1 · Answer 6 · answered Nov 06 '20 at 10:37

it should be path problem. go to windows search for python idle right click idle - open file location where right click on python.exe - open file location if the module not in that location type cmd and press enter in path now install module with pip install cython it will work fine

score 1 · Answer 7 · answered Dec 13 '21 at 08:03

I personally ran into this problem when I was trying to set up a new virtual environment. I simply installed Cython with python -m pip install Cython and then proceeded to install all the rest of my stuff I needed with python -m pip install -r requirements.txt. Once it was done, it actually uninstalled Cython for me... Why? Heck do I know... I ain't that kind of expert :<

ImportError: No module named 'Cython'

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