On 2 July, 2000 Steve Alexander wrote:
If you just want ids that are unique to a folder, try the following algorithm (taken originally from the Discussion object code in the PTK). The variable "self" is the one passed to the constructor method of a particular Python class, and represents the folder you want to put the new object into. I'm assuming the object is a "FooBar Item". The "foobar-%06d" bit generates a unique id for the object that looks like "foobar-290172837", based on the current time.
id = int(DateTime().timeTime()) while hasattr(self, str(id)): id = id +1 id = 'foobar-%09d' % id
The advantage of this approach is that there is very little contention in most cases.
I just looked back over some code where I used this algorithm, and I realised that it doesn't actually work :-( The identifiers that are searched for do not reflect the identifiers that are produced. The original code from the PTK does work. Here it is, adapted very slightly: # Find an unused id in location id = int(DateTime().timeTime()) while hasattr(self, `id`): id = id + 1 return id Here's my own, now fixed, code. Note the addition of a "max_tries" variable. if id == 'auto' or id == None: n = int(DateTime().timeTime()) max_tries = 10 fk = lambda key: 'foobar-%d' % key # function to format key id = fk(n) while max_tries and hasattr(self, str(id)): n = n + 1 max_tries = max_tries-1 id = fk(n) Sorry for posting such rubbish the first time around :-/ -- Steve Alexander Software Engineer Cat-Box limited http://www.cat-box.net