Determinig position of a element in a list
Pedro Werneck
pedro.werneck at bol.com.br
Mon Aug 25 16:20:53 EDT 2003
On Tue, 26 Aug 2003 00:29:04 +0200
"Przemo Drochomirecki" <pedrosch at gazeta.pl> wrote:
> i can implement function index (e.x. index(5,A) = -1, index(7,A) = 2),
> but maybe there's is simpler(builtin?) solution
I have a strange feeling that I misunderstood your question,
because the list.index() builtin is pretty obvious:
list.index(value, [start, [stop]])
If this is what you want, maybe you can use something like this:
def index(value, lst):
try:
i = list.index(lst, value)
return i
except ValueError:
return -1
a = [1,3,7,11,14,15]
assert index(3, a) == 1
assert index(12, a) == -1
or maybe:
class Ilist(list):
def index(self, *args):
try:
i = list.index(self, *args)
return i
except ValueError:
return -1
a = Ilist([1,3,7,11,14,15])
assert a.index(3) == 1
assert a.index(12) == -1
Rgds
Pedro
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