481๐
Django 1.6 (released Nov 2013) introduced the convenience methods first()
and last()
which swallow the resulting exception and return None
if the queryset returns no objects.
173๐
You can use array slicing:
Entry.objects.all()[:1].get()
Which can be used with .filter()
:
Entry.objects.filter()[:1].get()
You wouldnโt want to first turn it into a list because that would force a full database call of all the records. Just do the above and it will only pull the first. You could even use .order_by()
to ensure you get the first you want.
Be sure to add the .get()
or else you will get a QuerySet back and not an object.
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57๐
Now, in Django 1.9 you have first()
method for querysets.
YourModel.objects.all().first()
This is a better way than .get()
or [0]
because it does not throw an exception if queryset is empty, Therafore, you donโt need to check using exists()
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8๐
This could work as well:
def get_first_element(MyModel):
my_query = MyModel.objects.all()
return my_query[:1]
if itโs empty, then returns an empty list, otherwise it returns the first element inside a list.
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7๐
If you plan to get first element often โ you can extend QuerySet in this direction:
class FirstQuerySet(models.query.QuerySet):
def first(self):
return self[0]
class ManagerWithFirstQuery(models.Manager):
def get_query_set(self):
return FirstQuerySet(self.model)
Define model like this:
class MyModel(models.Model):
objects = ManagerWithFirstQuery()
And use it like this:
first_object = MyModel.objects.filter(x=100).first()
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4๐
It can be like this
obj = model.objects.filter(id=emp_id)[0]
or
obj = model.objects.latest('id')
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3๐
You should use django methods, like exists. Its there for you to use it.
if qs.exists():
return qs[0]
return None
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0๐
You can get the first object with these ways as shown below:
MyModel.objects.first()
MyModel.objects.all().first()
MyModel.objects.all()[0]
MyModel.objects.filter().first()
MyModel.objects.filter()[0]
In addition, you can get the last object with these ways as shown below:
MyModel.objects.last()
MyModel.objects.all().last()
MyModel.objects.filter().last()
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