C ++-使用numpy嵌入Python

Question

I would like to call a python function from C++ and get the return value. I've been able to do that with an easy multiply python function using this website's example code in section 5.3. To compile my program, I would run g++ test.cpp -I/usr/include/python2.7 -lpython2.7 . However, the python function I want to run imports numpy. When I try to run my program that is similar to the one on the code example mentioned above, I get an "ImportError: cannot import name _remove_dead_weakref". The full error is here:

Traceback (most recent call last):
  File "/home/osboxes/Desktop/test.py", line 1, in <module>
    import numpy as np 
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/__init__.py", line 142, in <module>
    from . import add_newdocs
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/add_newdocs.py", line 13, in <module>
    from numpy.lib import add_newdoc
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/lib/__init__.py", line 8, in <module>
    from .type_check import *
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/lib/type_check.py", line 11, in <module>
    import numpy.core.numeric as _nx
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/core/__init__.py", line 74, in <module>
    from numpy.testing.nosetester import _numpy_tester
  File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/testing/__init__.py", line 10, in <module>
    from unittest import TestCase
  File "/home/osboxes/miniconda2/lib/python2.7/unittest/__init__.py", line 64, in <module>
    from .main import TestProgram, main
  File "/home/osboxes/miniconda2/lib/python2.7/unittest/main.py", line 7, in <module>
    from . import loader, runner
  File "/home/osboxes/miniconda2/lib/python2.7/unittest/runner.py", line 7, in <module>
    from .signals import registerResult
  File "/home/osboxes/miniconda2/lib/python2.7/unittest/signals.py", line 2, in <module>
    import weakref
  File "/home/osboxes/miniconda2/lib/python2.7/weakref.py", line 14, in <module>
    from _weakref import (
ImportError: cannot import name _remove_dead_weakref

Some information: Python version is Python 2.7.14 :: Anaconda, Inc. (Is there a difference between python 2.7.14 and my version which has anaconda, inc. at the end?) The python program also runs just fine by itself. Any help would be appreciated. Thanks!

Edit: The path was being all weird with some parts going to my local python and numpy going to miniconda's python. Uninstalling miniconda as it wasn't needed for me fixed it.

Answer 1

This is happening because your environment is mixing two different Python installations. You can see it jump between them here:

File "/home/osboxes/.local/lib/python2.7/site-packages/numpy/testing/__init__.py"
File "/home/osboxes/miniconda2/lib/python2.7/unittest/__init__.py"

So you start out in /home/osboxes/.local/lib/python2.7/site-packages which is the Python installed by some system package manager (or perhaps even explicitly installed from source). But then it jumps to /home/osboxes/miniconda2/lib/python2.7 which is from Conda.

Since it appears you are intending to use Python from Conda, you need to install NumPy using Conda (so it is loaded from miniconda2 and not .local , and build your code using something like -I/home/osboxes/miniconda2/include/python2.7 instead of -I/usr/include/python2.7 .