Searching and manipulating lists of tuples

[Gerard Flanagan]

MTD wrote:
> Hello,
>
> I'm wondering if there's a quick way of resolving this problem.
>
> In a program, I have a list of tuples of form (str,int), where int is a
> count of how often str occurs
>
> e.g. L = [ ("X",1),("Y",2)] would mean "X" occurs once and "Y" occurs
> twice
>
> If I am given a string, I want to search L to see if it occurs already.
> If it does, I find the corresponding tuple and increment the integer
> part. If not, I append the new element with int = 1.
>
> e.g.
>
> algorithm(L, "X") would produce output L = [("X",2),("Y",2)]
> algorithm(L,"Z") would produce L = [("X",1),("Y",2),("Z",1)]
>

just a thought:

class MyList(object):

    def __init__(self):
        self._items = []
        self._counts = []

    def append(self, value):
        try:
            i = self._items.index(value)
            self._counts[i] += 1
        except ValueError:
            self._items.append(value)
            self._counts.append(1)

    def __getitem__(self, index):
        return self._items[index], self._counts[index]

    def __repr__(self):
        return str(zip(self._items, self._counts))

m = MyList()

print m
m.append('K')
print m
m.append('K')
print m
m.append('Z')
print m

-----------------------------------

Gerard