How do I import function from .pyx file in python?

Question

I'm trying to run Hadoopy, which has a file _main.pyx, and import _main is failing with module not found in __init__.py.

I'm trying to run this on OS X w/ standard python 2.7.

Answer 1

Add this code before you try to import _main:

import pyximport
pyximport.install()

Note that pyximport is part of Cython, so you'll have to install that if it isn't already.

Answer 2

You need to make sure you have followed all steps:

1. Install the Cython package using pip

   pip install Cython
   

2. Create a Cython file bbox.pyx

   cimport cython
   import numpy as np
   cimport numpy as np
   
   DTYPE = np.float32
   ctypedef np.float32_t DTYPE_t
   
   @cython.boundscheck(False)
   def compare_bboxes(
          np.ndarray[DTYPE_t, ndim=2] boxes1,
          np.ndarray[DTYPE_t, ndim=2] boxes2):
    ...
   

3. Create setup.py in the same directory

   from distutils.core import setup, Extension
   from Cython.Build import cythonize
   import numpy
   
   package = Extension('bbox', ['bbox.pyx'], include_dirs=[numpy.get_include()])
   setup(ext_modules=cythonize([package]))
   

4. Build the Cython

   python3 setup.py build_ext --inplace
   

5. Create your main python script run.py in the same directory

   import pyximport
   pyximport.install(setup_args={"script_args" : ["--verbose"]})
   from bbox import compare_bboxes
   
   def main(args):
      boxes1 = args.boxes1
      boxes2 = args.boxes2
      result = compare_bboxes(boxes1, boxes2)
   

6. Run your main script in the same directory

   python run.py