用inspect.getsource查看源码

python标准库中的inspect模块，可以用来在运行时查看很多有用的信息。其getsource函数，就是用来查看对象的源码。

>>> import inspect
>>> import json
>>> print(inspect.getsource(json.load))
def load(fp, *, cls=None, object_hook=None, parse_float=None,
        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
    """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
    a JSON document) to a Python object.

    ``object_hook`` is an optional function that will be called with the
    result of any object literal decode (a ``dict``). The return value of
    ``object_hook`` will be used instead of the ``dict``. This feature
    can be used to implement custom decoders (e.g. JSON-RPC class hinting).

    ``object_pairs_hook`` is an optional function that will be called with the
    result of any object literal decoded with an ordered list of pairs.  The
    return value of ``object_pairs_hook`` will be used instead of the ``dict``.
    This feature can be used to implement custom decoders.  If ``object_hook``
    is also defined, the ``object_pairs_hook`` takes priority.

    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
    kwarg; otherwise ``JSONDecoder`` is used.
    """
    return loads(fp.read(),
        cls=cls, object_hook=object_hook,
        parse_float=parse_float, parse_int=parse_int,
        parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)

也算是一种很方便的查看源码的方式。它的方便之处在于，你不用去很费劲地寻找源码所在的位置，用inspect.getsource直接将源码显示出来。

想知道引入对象的文件也可以，用inspect.getfile：

>>> inspect.getfile(json)
'/usr/local/python-3.8.5/lib/python3.8/json/__init__.py'
>>> inspect.getfile(json.load)
'/usr/local/python-3.8.5/lib/python3.8/json/__init__.py'

-- EOF --

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