Slow comparison between two lists

[Jani Tiainen]

I have rather simple 'Address' object that contains streetname,
number, my own status and x,y coordinates for it. I have two lists
both containing approximately 30000 addresses.

I've defined __eq__ method in my class like this:

    def __eq__(self, other):
        return self.xcoord == other.xcoord and \
            self.ycoord == other.ycoord and \
            self.streetname == other.streetname and \
            self.streetno == other.streetno

But it turns out to be very, very slow.

Then I setup two lists:

list_external = getexternal()
list_internal = getinternal()

Now I need get all all addresses from 'list_external' that are not in
'list_internal', and mark them as "new".

I did it like this:

for addr in list_external:
    if addr not in list_internal:
        addr.status = 1 # New address

But in my case running that loop takes about 10 minutes. What I am
doing wrong?

--

Jani Tiainen