Mixing cdef and regular python attributes in cdef class

by

Does this mean once you define a python class with cdef all self.* attributes have to be cdef defined?

Yes. This is stated pretty explicitly in the documentation:

Attributes in cdef classes behave differently from attributes in regular classes:

  • All attributes must be pre-declared at compile-time
  • …

You can quite happily store a string by defining the attribute to be of type object:

cdef public object msg

Internally, the reason for this is that the cdef class does not have a dictionary, which saves space and makes attribute access faster, but it does mean that it cannot have arbitrary attributes added at runtime. This is reasonably similar to using __slots__ in a normal Python class.

More Related Contents:

  1. Make executable file from multiple pyx files using cython
  2. Compiling with cython and mingw produces gcc: error: unrecognized command line option ‘-mno-cygwin’
  3. What is the recommended way of allocating memory for a typed memory view?
  4. Force NumPy ndarray to take ownership of its memory in Cython
  5. Wrapping a C library in Python: C, Cython or ctypes?
  6. Verifying compatibility in compiling extension types, and using them with cdef
  7. Can Cython compile to an EXE?
  8. Compile main Python program using Cython
  9. How to tell distutils to use gcc?
  10. calling dot products and linear algebra operations in Cython?
  11. Why does numpy.zeros takes up little space
  12. How to profile cython functions line-by-line
  13. Simple wrapping of C code with cython
  14. Interpretation vs dynamic dispatch penalty in Python
  15. Numpy vs Cython speed
  16. Running Cython in Windows x64 – fatal error C1083: Cannot open include file: ‘basetsd.h’: No such file or directory
  17. Cython class AttributeError
  18. How to compile .c code from Cython with gcc
  19. Filtering (reducing) a NumPy Array
  20. Fortran – Cython Workflow
  21. Difference between np.int, np.int_, int, and np.int_t in cython?
  22. Definition of def, cdef and cpdef in cython
  23. Using Cython To Link Python To A Shared Library
  24. cython shared memory in cython.parallel.prange – block
  25. Wrapping a pre-initialized pointer in a cython class
  26. Cython: (Why / When) Is it preferable to use Py_ssize_t for indexing?
  27. Large Performance difference when summing ints vs floats in Cython vs NumPy
  28. Passing numpy arrays in Cython to a C function that requires dynamically allocated arrays
  29. numpy faster than numba and cython , how to improve numba code
  30. reload module with pyximport?

Leave a Comment