不要用Cython扩展类型支持类的属性？ [英] Do Cython extension types support class attributes?

问题描述

Python类可以有类属性：

 类Foo（对象）：
   巴= 4
 

有没有在用Cython扩展类型定义类的属性类似的结构？例如，当我尝试编译下面用Cython code

  CDEF类Foo：
    CDEF INT酒吧
    巴= 4
 

我得到这个错误：

  thing.c：773：3：错误：使用未声明的标识符酒吧的
  巴= 4;
  ^
产生1个错误。
错误：命令'CC'，退出状态1失败
 

解决方案

虽然它似乎并不可能有C-类型的静态属性，用Cython扩展类型可以有这也是在Python自动访问正规Python静态属性。刚刚宣布他们为你将宣布他们的Python：

CDEF类Foo：
    巴= 4


生成的code表明，如果你在使用C-类型的上下文中使用它们这些静态属性被存储在类对象，即属性字典Python对象，它们是从Python对象转换回。

Python classes can have class attributes:

class Foo(object):
   bar = 4

Is there an analogous construct for defining class attributes in Cython extension types? For example, when I try to compile the following cython code

cdef class Foo:
    cdef int bar
    bar = 4

I get this error:

thing.c:773:3: error: use of undeclared identifier 'bar'
  bar = 4;
  ^
1 error generated.
error: command 'cc' failed with exit status 1

解决方案

While it doesn't seem to be possible to have C-typed static attributes, Cython extension types can have regular Python static attributes which are also automatically accessible in Python. Just declare them as you would declare them in Python:

cdef class Foo:
    bar = 4

The generated code shows that these static attributes are stored as Python objects in the attribute dict of the class object, i.e. if you use them in contexts where C-types are used, they are converted back from Python objects.

这篇关于不要用Cython扩展类型支持类的属性？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！