calculate the followers difference/grow by day

[João Paulo]

 
Hey guys,

I´m using SQLite and trying to calculate the followers difference by day

This is my model:

class Statistics(models.Model):

    followers = models.IntegerField()

    last_update = models.DateTimeField(auto_now_add=True)

This are my database rows:

"6" "50" "2018-05-29 00:25:48.276102"
"1" "100" "2018-05-29 00:26:48.276102"

"3" "200" "2018-05-30 00:27:04.178444"

"5" "250" "2018-05-30 00:30:04.178444"

"4" "300" "2018-05-31 00:27:04.178444"

And the result I´m tryting to achieve is:

followers | last_update
150          2018-05-30
50           2018-05-31

# I´m new to Django and thinking about use a Manager, but don't know if´s doable using a Manager
# Does anyone has a suggestion ?

[Daniel Germano Travieso]

Hello!

I don't quite understand what you mean by the followers difference by day, but as that difference by day is not a property of each model tuple, but a property of a specific day, you can write a view to handle that processing. Custom model Managers are used to either add manager methods or to customize and change the QuerySet your model returns. If you wish to use the model manager for this, it could be used to add a field to your model that makes a query to the last followers on that day and calculates the difference (?). You could also use a @property on your Model class for that too.

Hope it helps!

[]'s

Daniel Germano Travieso

Engenharia da Computação Turma: 013

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[James Farris]

I think you can do something like this

stats = Statistics.objects.all().order_by('-last_update')

latest_stat = 0

for stat in stats:

print(abs(latest_stat - stat.followers))

latest_stat = stat.followers

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