CSV export function from my personal finance mini-hackathon http://ollieglass.com/2013/01/30/personal-finance-mini-hackathon

CSV export function.py

def weeks(self):
    final_date = Transaction.objects.all().order_by('-transaction_date')[0].transaction_date
    
    start_date = Transaction.objects.all().order_by('transaction_date')[0].transaction_date
    end_date = start_date + datetime.timedelta(weeks=1)

    while end_date <= final_date:
        yield start_date, end_date

        start_date += datetime.timedelta(weeks=1)
        end_date += datetime.timedelta(weeks=1)


def handle(self, *args, **options):

    headers = ['Week'] + [category.name for category in Category.objects.all()] + ['Not set']
    print ",".join([str(item) for item in headers])

    for start_date, end_date in self.weeks():    
        transactions = Transaction.objects.filter(transaction_date__gte=start_date, transaction_date__lt=end_date)

        row = [str(start_date)]
        for category in Category.objects.all():
            total = 0
            for x in transactions.filter(merchant__category=category):
                total += x.billing_amount

            row.append(total)

        total = 0
        for x in transactions.filter(merchant__category=None):
            total += x.billing_amount

        row.append(total)

        print ",".join([str(item) for item in row])


    exit()