django-orchestra/orchestra/models/queryset.py

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2014-07-25 13:27:31 +00:00
def group_by(qset, *fields):
""" group_by iterator with support for multiple nested fields """
def nest(objects, ix):
objs = []
result = []
first = True
for obj in objects:
current = getattr(obj, fields[ix])
if first or current == previous:
objs.append(obj)
else:
if ix < len(fields)-1:
objs = nest(list(objs), ix+1)
result.append((previous, objs))
objs = [obj]
previous = current
first = False
if ix < len(fields)-1:
objs = nest(list(objs), ix+1)
result.append((current, objs))
return result
objs = []
first = True
for obj in qset.order_by(*fields):
current = getattr(obj, fields[0])
if first or current == previous:
objs.append(obj)
else:
if len(fields) > 1:
objs = nest(objs, 1)
yield previous, objs
objs = [obj]
previous = current
first = False
if len(fields) > 1:
objs = nest(objs, 1)
yield current, objs