Numpy import error Python3 on Raspberry Pi?

Question

When I try to import numpy in Python3 i get an error.
I installed it via pip3 and it got installed succesfully.

sudo pip3 install numpy 

Here is the error message when i try to import numpy:

Python 3.5.3 (default, Sep 27 2018, 17:25:39) [GCC 6.3.0 20170516] on linux Type "help", "copyright", "credits" or "license" for more information. >>> import numpy Traceback (most recent call last):   File "/usr/local/lib/python3.5/dist-packages/numpy/core/__init__.py", line 16, in <module>     from . import multiarray ImportError: libf77blas.so.3: cannot open shared object file: No such file or directory  During handling of the above exception, another exception occurred:  Traceback (most recent call last):   File "<stdin>", line 1, in <module>   File "/usr/local/lib/python3.5/dist-packages/numpy/__init__.py", line 142, in <module>     from . import add_newdocs   File "/usr/local/lib/python3.5/dist-packages/numpy/add_newdocs.py", line 13, in <module>     from numpy.lib import add_newdoc   File "/usr/local/lib/python3.5/dist-packages/numpy/lib/__init__.py", line 8, in <module>     from .type_check import *   File "/usr/local/lib/python3.5/dist-packages/numpy/lib/type_check.py", line 11, in <module>     import numpy.core.numeric as _nx   File "/usr/local/lib/python3.5/dist-packages/numpy/core/__init__.py", line 26, in <module>     raise ImportError(msg) ImportError: Importing the multiarray numpy extension module failed.  Most likely you are trying to import a failed build of numpy. If you're working with a numpy git repo, try `git clean -xdf` (removes all files not under version control).  Otherwise reinstall numpy.  Original error was: libf77blas.so.3: cannot open shared object file: No such file or directory 

Answer 1

Moving my comment to an answer because it seemed helpful to a few users.

You are missing a core numpy dependency. Running

sudo apt-get install python-dev libatlas-base-dev 

should fix the problem.

If that doesn't work, you can try installing RPi specific versions of numpy, see comments here.

Answer 2

I am going to add an answer as I don't have enough reputation to comment.

I had this issue on my Raspberry Pi 4.

In my case this was fixed simply by running this in the command line:

sudo apt-get install libatlas-base-dev 

I thought initially I was missing a python module dependency, but this is a unix dependency, its shouldn't affect you python virtual environment