how can I avoid abusing lists?

[Simon Forman]

Thomas Nelson wrote:
> I have this code:
> type1 = [0]
> type2 = [0]
> type3 = [0]
> map = {0:type1, 1:type1, 2:type3, 3:type1, 4:type2}  # the real map is
> longer than this
>
> def increment(value):
> 	map[value][0] += 1
>
> increment(1)
> increment(1)
> increment(0)
> increment(4)
> #increment will actually be called many times through other functions
> print type1[0], type2[0], type3[0]
> #should print "3 1 0"
>
> This is exactly what I want to do: every time I encounter this kind of
> value in my code, increment the appropriate type by one.  Then I'd like
> to go back and find out how many of each type there were.  This way
> I've written seems simple enough and effective, but it's very ugly and
> I don't think it's the intended use of lists.  Does anyone know a
> cleaner way to have the same funtionality?
>
> Thanks,
> THN

In this case, lists are unnecessary.  Just use ints.

Since your "type codes" are ints, you can create your map like this
(assuming 10 types):

map = dict((n, 0) for n in range(10))


Then your increment function becomes:

def increment(value):
	map[value] += 1


And instead of,
print type1[0], type2[0], type3[0]

say,
print map[0], map[1], map[2]


Peace,
~Simon