Danny Yoo said unto the world upon 2005-12-11 22:13: > > On Sun, 11 Dec 2005, Brian van den Broek wrote: > > >>I have a case like this toy code: >> >>import random >>list1 = [1,2,3] >>list2 = ['a', 'b', 'c'] >>item = random.choice(list1 +list2) >>if item in list1: >> others = list2 >>else: >> others = list1 > > > Hi Brian, > > This code works, and as long as you give it a good function name, I think > it's fine the way it is. > > If we're concerned with efficiency,
Hi Danny, thanks for the reply. My concern wasn't efficiency, but screen space. I'm refactoring some code and had a method that was too long. I was trying to fix it while avoiding real work :-) > we might want to change the > random.choice() call to a random.randrange(), to avoid building the > concatenation of list1 and list2. This looks like: > > #### > def sampleFromTwoLists(list1, list2): > """Given two lists, returns a random element out of one of the lists > as well as the other list.""" > index = random.randrange(len(list1) + len(list2)) > if index < len(list1): > return list1[index], list2 > else: > return list2[index - len(list1)], list1 > #### > > Just out of curiosity, are you planning to do some kind of stratified > sampling with this? Thanks for the example. Nothing so interesting as that, I'm afraid :-) I'm just goofing around with a text-based game, so efficiency isn't an issue. The two list represent teams of characters and the point of the code is to select a random character and oppose them to the other team. >>Another way occurred to me, but I wonder if I'm being too cute: >> >>item = random.choice(list1 +list2) >>others = [list1, list2][item in list1] > > > Too cute. *grin* Although it's concise, I'm having a hard time reading > it. Thanks for the feedback. I still don't trust my intuitions on issues like this. Best to all, Brian vdB _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
