Question

I’ve got a model similar to this:

class Person(models.Model):
    name = models.CharField(max_length=40)
    birthday = DateTimeField() # their next birthday

I would like to get a list of the total birthdays for each day for the next 30 days. So for example, the list would look like this:

[[9, 0], [10, 3], [11, 1], [12, 1], [13, 5], ... #30 entries in list 

Each list entry in the list is a date number followed by the number of birthdays on that day. So for example on the 9th of May there are 0 birthdays.

UPDATES

My db is sqlite3 – will be moving to postgres in the future.

Answer 1

I would get the list of days and birthday count this way:

from datetime import date, timedelta    
today = date.today()
thirty_days = today + timedelta(days=30)

# get everyone with a birthday
people = Person.objects.filter(birthday__range=[today, thirty_days])

birthday_counts = []
for date in [today + timedelta(x) for x in range(30)]:
    # use filter to get only birthdays on given date's day, use len to get total
    birthdays = [date.day, len(filter(lambda x: x.birthday.day == date.day, people))]
    birthday_counts.append(birthdays)