jim stockford wrote: > from > http://docs.python.org/lib/built-in-funcs.html > some functions are always available--the built-in functions. > > (from elsewhere) everything in python is an object. > > -------------------- > > hey, from abs() to zip() there's type() and super() and str() > and setattr() and ... dir() and... they're the built-ins > > my question: what.abs() what.zip() etc.? > > I think there must be a base object, a la java or Nextstep, > that supports these functions. what is it? > > maybe it's not practical, but it's driving me nuts anyway. > thanks in advance. > > > _______________________________________________ > Tutor maillist - Tutor@python.org > http://mail.python.org/mailman/listinfo/tutor > > Hi Jim, in Python function are objects also.
>>> def test_func(): ... return 1 >>> abs.__class__.__name__ 'builtin_function_or_method' >>> test_func.__class__.__name__ 'function' >>> from types import FunctionType, BuiltinFunctionType >>> isinstance(abs, BuiltinFunctionType) True >>> isinstance(test_func, FunctionType) True Each function is an object. When you call foo() It's actually shorthand for foo.__call__() Try the dir() command - it lists all attributes of an object. For instance: >>> dir(abs) ['__call__', '__class__', '__cmp__', '__delattr__', '__doc__', '__getattribute__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__self__', '__setattr__', '__str__'] >>> dir(test_func) ['__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__get__', '__getattribute__', '__hash__', '__init__', '__module__', '__name__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__str__', 'func_closure', 'func_code', 'func_defaults', 'func_dict', 'func_doc', 'func_globals', 'func_name'] This means that unlike Java you can pass functions as arguments to other functions/methods - it also means you don't need to wrap everything in a class unnecessarily - in Python you only use a class when you need a class, not because Sun decided that classes were good. ;-) Regards, Liam Clarke _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
