Discover Members of a Function/Class
If you ever need to find out what members a function or class has, you can use the following trick (this example uses the "json" class):
# New unknown script package I have never used before
import json
# Find out all members in this package
for item in dir(json):
print itemWhich will output the following:
JSONDecoder
JSONEncoder
__all__
__author__
__builtins__
__doc__
__file__
__name__
__package__
__path__
__version__
_default_decoder
_default_encoder
decoder
dump
dumps
encoder
load
loads
scannerYou can even print the docstring from a class using the syntax like the following example for "json.dump":
print json.dump.__doc__Which should output:
"""
Serialize ``obj`` as a JSON formatted stream to ``fp`` (a
``.write()``-supporting file-like object).
If ``skipkeys`` is true then ``dict`` keys that are not basic types
(``str``, ``unicode``, ``int``, ``long``, ``float``, ``bool``, ``None``)
will be skipped instead of raising a ``TypeError``.
If ``ensure_ascii`` is true (the default), all non-ASCII characters in the
output are escaped with ``\uXXXX`` sequences, and the result is a ``str``
instance consisting of ASCII characters only. If ``ensure_ascii`` is
``False``, some chunks written to ``fp`` may be ``unicode`` instances.
This usually happens because the input contains unicode strings or the
``encoding`` parameter is used. Unless ``fp.write()`` explicitly
understands ``unicode`` (as in ``codecs.getwriter``) this is likely to
cause an error.
If ``check_circular`` is false, then the circular reference check
for container types will be skipped and a circular reference will
result in an ``OverflowError`` (or worse).
If ``allow_nan`` is false, then it will be a ``ValueError`` to
serialize out of range ``float`` values (``nan``, ``inf``, ``-inf``)
in strict compliance of the JSON specification, instead of using the
JavaScript equivalents (``NaN``, ``Infinity``, ``-Infinity``).
If ``indent`` is a non-negative integer, then JSON array elements and
object members will be pretty-printed with that indent level. An indent
level of 0 will only insert newlines. ``None`` is the most compact
representation. Since the default item separator is ``', '``, the
output might include trailing whitespace when ``indent`` is specified.
You can use ``separators=(',', ': ')`` to avoid this.
If ``separators`` is an ``(item_separator, dict_separator)`` tuple
then it will be used instead of the default ``(', ', ': ')`` separators.
``(',', ':')`` is the most compact JSON representation.
``encoding`` is the character encoding for str instances, default is UTF-8.
``default(obj)`` is a function that should return a serializable version
of obj or raise TypeError. The default simply raises TypeError.
If *sort_keys* is ``True`` (default: ``False``), then the output of
dictionaries will be sorted by key.
To use a custom ``JSONEncoder`` subclass (e.g. one that overrides the
``.default()`` method to serialize additional types), specify it with
the ``cls`` kwarg; otherwise ``JSONEncoder`` is used.
"""