objectoriented -?- functional

[Armin]

On Wednesday 18 March 2009 10:19:41 Peter Otten wrote:
> Walther Neuper wrote:
> > loving Java (oo)
>
> Don't mind, weirder things have happened
>
> http://wiki.muenster.org/index.php/Schwan
>

LOL!!

> > as well as SML (fun) I use to practice both of them
> > separately.
> > Now, with Python I would like to combine 'oo.extend()' with 'functional
> > map':
> >
> > Python 2.4.4 (#2, Oct 22 2008, 19:52:44)
> > [GCC 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)] on linux2
> > Type "help", "copyright", "credits" or "license" for more information.
> >
> >  >>> def reverse_(list):
> >
> > ...     """list.reverse() returns None; reverse_ returns the reversed
> > list"""
> > ...     list.reverse()
> > ...     return list
> > ...
> >
> >  >>> ll = [[11, 'a'], [33, 'b']]
> >  >>> l = ll[:]  # make a copy !
> >  >>> l = map(reverse_, l[:])  # make a copy ?
> >  >>> ll.extend(l)
> >  >>> print("ll=", ll)
> >
> > ('ll=', [['a', 11], ['b', 33], ['a', 11], ['b', 33]])
> >
> > But I expected to get ...
> > ('ll=', [[11, 22], [33, 44], [22, 11], [44, 33]])
> > ... how would that elegantly be achieved with Python ?
>
> Sorry, I cannot infer the pattern. How would you do that at all?
>
> Peter
> --
> http://mail.python.org/mailman/listinfo/python-list

If you want to reimplement list.extend() (as I understand?) you will have to 
subclass it and change the behaviour.

-- 
Armin Moradi