Django provides a few classes that help you manage paginated data – that is, data that’s split across several pages, with “Previous/Next” links. These classes live in django/core/paginator.py.
For examples, see the Pagination topic guide.
Paginator
class¶A paginator acts like a sequence of Page
when using len()
or
iterating it directly.
Required. A list, tuple, QuerySet
, or other sliceable object with a
count()
or __len__()
method. For consistent pagination,
QuerySet
s should be ordered, e.g. with an
order_by()
clause or with a default
ordering
on the model.
Performance issues paginating large QuerySet
s
If you’re using a QuerySet
with a very large number of items,
requesting high page numbers might be slow on some databases, because
the resulting LIMIT
/OFFSET
query needs to count the number of
OFFSET
records which takes longer as the page number gets higher.
Required. The maximum number of items to include on a page, not including
orphans (see the orphans
optional argument below).
Optional. Use this when you don’t want to have a last page with very few
items. If the last page would normally have a number of items less than or
equal to orphans
, then those items will be added to the previous page
(which becomes the last page) instead of leaving the items on a page by
themselves. For example, with 23 items, per_page=10
, and orphans=3
,
there will be two pages; the first page with 10 items and the second
(and last) page with 13 items. orphans
defaults to zero, which means
pages are never combined and the last page may have one item.
Optional. Whether or not the first page is allowed to be empty. If
False
and object_list
is empty, then an EmptyPage
error will
be raised.
The error_messages
argument lets you override the default messages that
the paginator will raise. Pass in a dictionary with keys matching the error
messages you want to override. Available error message keys are:
invalid_page
, min_page
, and no_results
.
For example, here is the default error message:
>>> from django.core.paginator import Paginator
>>> paginator = Paginator([1, 2, 3], 2)
>>> paginator.page(5)
Traceback (most recent call last):
...
EmptyPage: That page contains no results
And here is a custom error message:
>>> paginator = Paginator(
... [1, 2, 3],
... 2,
... error_messages={"no_results": "Page does not exist"},
... )
>>> paginator.page(5)
Traceback (most recent call last):
...
EmptyPage: Page does not exist
Returns a Page
object with the given 1-based index, while also
handling out of range and invalid page numbers.
If the page isn’t a number, it returns the first page. If the page number is negative or greater than the number of pages, it returns the last page.
Raises an EmptyPage
exception only if you specify
Paginator(..., allow_empty_first_page=False)
and the object_list
is
empty.
Returns a Page
object with the given 1-based index. Raises
PageNotAnInteger
if the number
cannot be converted to an integer
by calling int()
. Raises EmptyPage
if the given page number
doesn’t exist.
Returns a 1-based list of page numbers similar to
Paginator.page_range
, but may add an ellipsis to either or both
sides of the current page number when Paginator.num_pages
is large.
The number of pages to include on each side of the current page number is
determined by the on_each_side
argument which defaults to 3.
The number of pages to include at the beginning and end of page range is
determined by the on_ends
argument which defaults to 2.
For example, with the default values for on_each_side
and on_ends
,
if the current page is 10 and there are 50 pages, the page range will be
[1, 2, '…', 7, 8, 9, 10, 11, 12, 13, '…', 49, 50]
. This will result in
pages 7, 8, and 9 to the left of and 11, 12, and 13 to the right of the
current page as well as pages 1 and 2 at the start and 49 and 50 at the
end.
Raises InvalidPage
if the given page number doesn’t exist.
A translatable string used as a substitute for elided page numbers in the
page range returned by get_elided_page_range()
. Default is
'…'
.
The total number of objects, across all pages.
Note
When determining the number of objects contained in object_list
,
Paginator
will first try calling object_list.count()
. If
object_list
has no count()
method, then Paginator
will
fall back to using len(object_list)
. This allows objects, such as
QuerySet
, to use a more efficient count()
method when
available.
Page
class¶You usually won’t construct Page
objects by hand – you’ll get them by
iterating Paginator
, or by using Paginator.page()
.
A page acts like a sequence of Page.object_list
when using
len()
or iterating it directly.
Returns the next page number. Raises InvalidPage
if next page
doesn’t exist.
Returns the previous page number. Raises InvalidPage
if previous
page doesn’t exist.
Returns the 1-based index of the first object on the page, relative to all
of the objects in the paginator’s list. For example, when paginating a list
of 5 objects with 2 objects per page, the second page’s
start_index()
would return 3
.
Returns the 1-based index of the last object on the page, relative to all
of the objects in the paginator’s list. For example, when paginating a list
of 5 objects with 2 objects per page, the second page’s
end_index()
would return 4
.
The list of objects on this page.
The 1-based page number for this page.
A base class for exceptions raised when a paginator is passed an invalid page number.
The Paginator.page()
method raises an exception if the requested page is
invalid (i.e. not an integer) or contains no objects. Generally, it’s enough
to catch the InvalidPage
exception, but if you’d like more granularity,
you can catch either of the following exceptions:
Raised when page()
is given a valid value but no objects
exist on that page.
Both of the exceptions are subclasses of InvalidPage
, so you can handle
them both with except InvalidPage
.
Oct 08, 2024