Jani Tiainen <[EMAIL PROTECTED]> writes: > 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?
The nested loop takes time proportional to the product of the number of elements in the loops. To avoid it, convert the inner loop to a set, which can be looked up in constant time: internal = set(list_internal) for addr in list_external: if addr in internal: addr.status = 1 -- http://mail.python.org/mailman/listinfo/python-list