which data structure to use?

[Robert Voigtländer]

Hi,

which would be the best data structure to use for the following case?

I have objects like this:

class Node(object): 
    def __init__(self, pos, parent, g , h): 
        self.pos = pos 
        self.parent = parent 
        self.g = g 
        self.h = h 
        self.f = g+h 


I need to build a "list" of these objects. The amount is unknown.
On this list I need to regularly

1. check if a specific item - identified by Node.pos - is in the list.
2. find the object with the lowest Node.f attribute and update or remove it


What would be a good approach. Using a list I always need to traverse the whole list to do one of the above actions.

Thanks
Robert