Question

If I’m making a simple grid based game, for example, I might have a few 2d lists. One might be for terrain, another might be for objects, etc. Unfortunately, when I need to iterate over the lists and have the contents of a square in one list affect part of another list, I have to do something like this.

for i in range(len(alist)):     for j in range(len(alist[i])):         if alist[i][j].isWhatever:             blist[i][j].doSomething() 

Is there a nicer way to do something like this?

Answer 1

I’d start by writing a generator method:

def grid_objects(alist, blist):     for i in range(len(alist)):         for j in range(len(alist[i])):             yield(alist[i][j], blist[i][j]) 

Then whenever you need to iterate over the lists your code looks like this:

for (a, b) in grid_objects(alist, blist):     if a.is_whatever():         b.do_something()