Piet van Oostrum wrote: >>>>>> kj <no.em...@please.post> (k) wrote: > >> k> Switching from Perl here, and having a hard time letting go... > >> k> Suppose I have an "array" foo, and that I'm interested in the 4th, 8th, >> k> second, and last element in that array. In Perl I could write: > >> k> my @wanted = @foo[3, 7, 1, -1]; > >> k> I was a bit surprised when I got this in Python: > >>>>>> wanted = foo[3, 7, 1, -1] >> k> Traceback (most recent call last): >> k> File "<stdin>", line 1, in <module> >> k> TypeError: list indices must be integers > >> k> Granted, Perl's syntax is often obscure and hard-to-read, but in >> k> this particular case I find it quite transparent and unproblematic, >> k> and the fictional "pythonized" form above even more so. > >> k> The best I've been able to come up with in Python are the somewhat >> k> Perl-like-in-its-obscurity: > >>>>>> wanted = map(foo.__getitem__, (3, 7, 1, -1)) > >> k> or the clearer but unaccountably sesquipedalian > >>>>>> wanted = [foo[i] for i in 3, 7, 1, -1] >>>>>> wanted = [foo[3], foo[7], foo[7], foo[-1]] > >> k> Are these the most idiomatically pythonic forms? Or am I missing >> k> something better? > > Do it yourself: > > class MyList(list): > def __getitem__(self, indx): > if isinstance (indx, tuple): > return [self[i] for i in indx] > else: > return list.__getitem__(self, indx) > > l = MyList((range(10))) > > print l[3, 7, 1, -1] > print l[3] > print l[3:7] > > # and now for something completely different > > print l[3, (7, 1), -1] >
even better: print l[3, 4:10:2, 7] -- http://mail.python.org/mailman/listinfo/python-list
