I have a question in Django on how you can compare dates to solve some solutions. For example I have a datefield in my models.py Like below.
class Invoice(models.Model):
payment_date = models.DateTimeField()
What I want to be able to do is ask if the is a way to compare a datetime.now with a DateTimeField. For example, if I had a list of payment dates and I wanted to compare with datetime now. Thhe payment_date's that are late with their payments are shown in owing. Otherwise, it the value is zero.
Here is my views to show whats going on. I have tried so far but I get a 0 value for payment_date's which are later than the payment date.
Edit here is my latest views. Funny thing is that I seem to be getting the owing = invoice_gross for all results - unlike before when I was getting all 0s. So it is still not working properly.
@login_required
def homepage(request):
invoices_list = Invoice.objects.all()
invoice_name = invoices_list[0].client_contract_number.client_number.name
invoice_gross = invoices_list[0].invoice_gross
payment_date = invoices_list[0].payment_date
if payment_date <= datetime.now():
owing = invoice_gross
if payment_date > datetime.now():
owing = 0
return render_to_response(('index.html', locals()), {'invoices_list': invoices_list ,'invoice_name':invoice_name, 'invoice_gross':invoice_gross,'payment_date':payment_date,'owing':owing}, context_instance=RequestContext(request))
Oh and my table is basically doing something like this.
ID Owing
1 100 (All the same value)
2 100
3 100
. .
. .
. .
You can use equal to comparison operator = to check if one datetime object is has same value as other. In the following program, we initialize two datetime objects, and then check if both datetime objects have same date and time.
Use the strptime(date_str, format) function to convert a date string into a datetime object as per the corresponding format . To get the difference between two dates, subtract date2 from date1. A result is a timedelta object.
I think the problem is in the line
if datetime.now() == payment_date:
That will literally see if the payment_date
is right now. I think you want to see if now is greater than or equal to the payment_date
, in which case you should use
if datetime.now() >= payment_date:
You can also just filter the invoices when you query the database:
invoices_list = Invoice.objects.filter(payment_date__lte=datetime.now())
Your code is wrong because you have mutually exclusive conditionals. Look:
if payment_date <= datetime.now():
owing = invoice_gross
if payment_date > datetime.now():
owing = 0
That first checks to see if payment_date
is before now. Then it sets owing
to invoice_gross
. Then, in the same conditional, it checks to see if payment_date
is after now. But that can't be! You are only in this block of code if payment_date
is before now!
I think you have an indentation error, and want this instead:
if payment_date <= datetime.now():
owing = invoice_gross
if payment_date > datetime.now():
owing = 0
Which, of course, is the same as:
if payment_date <= datetime.now():
owing = invoice_gross
else:
owing = 0
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