cython导入错误在同一软件包中

Question

I've seen this question and the answer don't seems to be working. Following is my directory structure.

.
├── my_package
│   ├── a.pyx
│   ├── b.pyx
│   ├── b.pxd
│   ├── test.py
│   └── __init__.py
└── setup.py

a.pyx file

cimport my_package.b  as b

class a:
    def __init__(self):
        self.b = b.b()
        self.b.run()

b.pyx file

cdef class b:

    def __init__(self):
        pass

    cpdef run(self):
        print "b is running"

b.pxd file

cdef class b:
    cpdef run(self)

test.py

import a

c = a.a()

setup.py

from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
import numpy

extensions = [
    Extension("my_package.a", ["my_package/a.pyx"]
        ),
    Extension("my_package.b", ["my_package/b.pyx"]
)
]

for e in extensions:
    e.cython_directives = {"embedsignature": True}

setup(
    name = "preprocess",
    ext_modules = cythonize(extensions),
)

after running python setup.py build_ext --inplace there is no compile error. But if I try to run test.py it gives ImportError: No module named my_package.b .

Any input will be appreciated.

BTW if we change the first line of a.pyx from cimport my_package.b as b to import b it will work.

Answer 1

For cimport of a sub-package to work, the package directory needs to contain an __init__.pxd .

It is the equivalent of __init__.py for cimport instead of import .

Make directory structure be like this:

.
├── my_package
│   ├── a.pyx
│   ├── b.pyx
│   ├── b.pxd
│   ├── test.py
│   └── __init__.py
│   └── __init__.pxd
└── setup.py

Then include pxd files as package data in setup.py so that they get installed:

from setuptools import setup, Extension
from Cython.Build import cythonize

extensions = [
    Extension("my_package.a", ["my_package/a.pyx"]
        ),
    Extension("my_package.b", ["my_package/b.pyx"]
)
]

for e in extensions:
    e.cython_directives = {"embedsignature": True}

package_data = {'my_package': ['*.pxd']}

setup(
    name = "preprocess",
    ext_modules = cythonize(extensions),
    include_package_data=True,
    package_data=package_data,
)

Note - import numpy should not be in setup.py as it will make installing package not work unless numpy has already been installed.

Put it in requirements.txt to have it installed along with the package.