python - 为什么此代码返回 'complex' ？

Question

# Example: provide pickling support for complex numbers.

try:
    complex
except NameError:
    pass
else:

    def pickle_complex(c):
        return complex, (c.real, c.imag) # why return complex here?

    pickle(complex, pickle_complex, complex)

为什么？
以下代码是被调用的pickle函数:

dispatch_table = {}

def pickle(ob_type, pickle_function, constructor_ob=None):
    if type(ob_type) is _ClassType:
        raise TypeError("copy_reg is not intended for use with classes")

    if not callable(pickle_function):
        raise TypeError("reduction functions must be callable")
    dispatch_table[ob_type] = pickle_function

    # The constructor_ob function is a vestige of safe for unpickling.
    # There is no reason for the caller to pass it anymore.
    if constructor_ob is not None:
        constructor(constructor_ob)

def constructor(object):
    if not callable(object):
        raise TypeError("constructors must be callable")

Answer 1

complex 是用于重构 pickle 对象的类。它被返回，以便可以与 real 和 imag 值一起进行 pickle。然后，当 unpickler 出现时，它会看到该类和一些值用作其构造函数的参数。 unpickler 使用给定的类和参数创建一个新的复杂对象，该对象与被pickle的原始对象等效。

这在copy_reg中有更详细的解释。和 pickle documentation .