A discussion in a recent question here (what-is-the-most-pythonic-way-to-have-a-generator-expression-executed) - that min/max() need objects to be comparable - made me wonder how do i find which Python types support particular method (__cmp__, or maybe __lt__ - specifics not important).
Pivotal to that seems to be ability to get list of all types, to start with. Then i can simply check hasattr(thisType, '__cmp__'). So how do i enumerate all data types there are?
Presence of the relational special methods isn't enough to guarantee comparability; the methods can still raise an exception if they don't like the specific type(s) passed to them.
>>> import __builtin__
>>> builtin_types= [t
... for t in __builtin__.__dict__.itervalues()
... if isinstance(t, type)]
>>> import pprint
>>> pprint.pprint(sorted(builtin_types, key=repr))
[<type 'basestring'>,
<type 'bool'>,
<type 'buffer'>,
<type 'bytearray'>,
<type 'classmethod'>,
<type 'complex'>,
<type 'dict'>,
<type 'enumerate'>,
<type 'exceptions.ArithmeticError'>,
<type 'exceptions.AssertionError'>,
<type 'exceptions.AttributeError'>,
<type 'exceptions.BaseException'>,
<type 'exceptions.BufferError'>,
<type 'exceptions.BytesWarning'>,
<type 'exceptions.DeprecationWarning'>,
<type 'exceptions.EOFError'>,
<type 'exceptions.EnvironmentError'>,
<type 'exceptions.Exception'>,
<type 'exceptions.FloatingPointError'>,
<type 'exceptions.FutureWarning'>,
<type 'exceptions.GeneratorExit'>,
<type 'exceptions.IOError'>,
<type 'exceptions.ImportError'>,
<type 'exceptions.ImportWarning'>,
<type 'exceptions.IndentationError'>,
<type 'exceptions.IndexError'>,
<type 'exceptions.KeyError'>,
<type 'exceptions.KeyboardInterrupt'>,
<type 'exceptions.LookupError'>,
<type 'exceptions.MemoryError'>,
<type 'exceptions.NameError'>,
<type 'exceptions.NotImplementedError'>,
<type 'exceptions.OSError'>,
<type 'exceptions.OverflowError'>,
<type 'exceptions.PendingDeprecationWarning'>,
<type 'exceptions.ReferenceError'>,
<type 'exceptions.RuntimeError'>,
<type 'exceptions.RuntimeWarning'>,
<type 'exceptions.StandardError'>,
<type 'exceptions.StopIteration'>,
<type 'exceptions.SyntaxError'>,
<type 'exceptions.SyntaxWarning'>,
<type 'exceptions.SystemError'>,
<type 'exceptions.SystemExit'>,
<type 'exceptions.TabError'>,
<type 'exceptions.TypeError'>,
<type 'exceptions.UnboundLocalError'>,
<type 'exceptions.UnicodeDecodeError'>,
<type 'exceptions.UnicodeEncodeError'>,
<type 'exceptions.UnicodeError'>,
<type 'exceptions.UnicodeTranslateError'>,
<type 'exceptions.UnicodeWarning'>,
<type 'exceptions.UserWarning'>,
<type 'exceptions.ValueError'>,
<type 'exceptions.Warning'>,
<type 'exceptions.ZeroDivisionError'>,
<type 'file'>,
<type 'float'>,
<type 'frozenset'>,
<type 'int'>,
<type 'list'>,
<type 'long'>,
<type 'object'>,
<type 'property'>,
<type 'reversed'>,
<type 'set'>,
<type 'slice'>,
<type 'staticmethod'>,
<type 'str'>,
<type 'str'>,
<type 'super'>,
<type 'tuple'>,
<type 'type'>,
<type 'unicode'>,
<type 'xrange'>]