Question

Background :- I am trying to merge 2 querysets from same model.
Something like this. i.e. every 3rd counter they should be merged.

queryset = get_foo(person)  #First queryset
promoted_foo = get_promoted_foo()  #Second queryset
for (counter,(s,p)) in enumerate(itertools.izip(queryset,promoted_foo)):
    if counter%3==0:
        queryset.insert(counter,promoted_foo.pop())
if promoted_foo:
   queryset.extend(promoted_foo)

What is the most Pythonic way to do this ?
I know I can use list() on the quersets and then merge them. But that consumes a lot of memory. So what can be a alternative to this?

Answer 1

You might define your own generator that lazily loads items from the querysets.

I haven’t tested this but something like:

def everythird():
    queryset = get_foo(person)  #First queryset
    promoted_foo = get_promoted_foo()  #Second queryset
    for (counter,(s,p)) in enumerate(itertools.izip(queryset,promoted_foo)):
    if counter%3==0 and promoted_foo:
        yield promoted_foo
    elif queryset:
        yield queryset