>>>>> 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]
duck :=)
--
Piet van Oostrum <p...@cs.uu.nl>
URL: http://pietvanoostrum.com [PGP 8DAE142BE17999C4]
Private email: p...@vanoostrum.org
--
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