"Phillip J. Eby" a écrit :
Try: data=(self.which_one and [self.second_data] or [self.first_data])[0]
wow. what a *clever* idea to use [] around self.???_data. I used to write: data=self.which_one and self.second_data or self.first_data but this failed because sometimes self.second_data is a "false" value (eg 0, '', instead of None that I use for empty values), causing self.first_data to be returned instead. one learns about python every day. thanks for the tip. As I wrote in an earlier post, my initial problem was solved using class_defaut_for_X trick
Offhand, I'd guess that there is probably a lot easier way to do what you're doing, and that you probably don't even need/want "id" to be a sequence, let alone some of the other things you're doing here. But without knowing what your app is actually trying to do, I can't suggest anything further. I'm writing an application to track issues. I can not just use DC's tracker product, because my customer's needs are very specials. Well, various entities in my application have a so called 'location'. I wish to be able to re-use the application I'm writing, so I abstracted the concept of 'location'. i have then a specialist to manage locations got from a location rack. The rack I wrote for my customer deals with two-headed locations: (site, subdivision). Each part of the location is managed in a different way, but I need the two to identify one's location. Later, when I install that program for a different customer, I want to be able to rip out the old location rack and put another location rack which can be more 'normal' (ie, one-headed) No one will notice except the key to get the location is now an integer (or a string) instead of a tuple.
So, I think I'm doing right to have an id which is a sequence. Thanks for your great help. I'm still fighting to acquire the principle behind zpatterns, but once I get it, I wish I could help others to understand it as well. regards, jephte.clain@univ-reunion.fr