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Fixed #27126 -- Made {% regroup %} return a namedtuple to ease unpacking.

This commit is contained in:
Baptiste Mispelon 2016-08-26 11:39:06 +02:00 committed by Tim Graham
parent 7968bb7fad
commit 61b45dff6b
4 changed files with 52 additions and 2 deletions

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@ -4,6 +4,7 @@ from __future__ import unicode_literals
import re
import sys
import warnings
from collections import namedtuple
from datetime import datetime
from itertools import cycle as itertools_cycle, groupby
@ -335,6 +336,9 @@ class LoremNode(Node):
return '\n\n'.join(paras)
GroupedResult = namedtuple('GroupedResult', ['grouper', 'list'])
class RegroupNode(Node):
def __init__(self, target, expression, var_name):
self.target, self.expression = target, expression
@ -355,7 +359,7 @@ class RegroupNode(Node):
# List of dictionaries in the format:
# {'grouper': 'key', 'list': [list of contents]}.
context[self.var_name] = [
{'grouper': key, 'list': list(val)}
GroupedResult(grouper=key, list=list(val))
for key, val in
groupby(obj_list, lambda obj: self.resolve_expression(obj, context))
]

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@ -896,13 +896,36 @@ resulting list. Here, we're regrouping the ``cities`` list by the ``country``
attribute and calling the result ``country_list``.
``{% regroup %}`` produces a list (in this case, ``country_list``) of
**group objects**. Each group object has two attributes:
**group objects**. Group objects are instances of
:py:func:`~collections.namedtuple` with two fields:
* ``grouper`` -- the item that was grouped by (e.g., the string "India" or
"Japan").
* ``list`` -- a list of all items in this group (e.g., a list of all cities
with country='India').
.. versionchanged:: 1.11
The group object was changed from a dictionary to a
:py:func:`~collections.namedtuple`.
Because ``{% regroup %}`` produces :py:func:`~collections.namedtuple` objects,
you can also write the previous example as::
{% regroup cities by country as country_list %}
<ul>
{% for country, local_cities in country_list %}
<li>{{ country }}
<ul>
{% for city in local_cities %}
<li>{{ city.name }}: {{ city.population }}</li>
{% endfor %}
</ul>
</li>
{% endfor %}
</ul>
Note that ``{% regroup %}`` does not order its input! Our example relies on
the fact that the ``cities`` list was ordered by ``country`` in the first place.
If the ``cities`` list did *not* order its members by ``country``, the

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@ -300,6 +300,10 @@ Templates
supports context processors by setting the ``'context_processors'`` option in
:setting:`OPTIONS <TEMPLATES-OPTIONS>`.
* The :ttag:`regroup` tag now returns ``namedtuple``\s instead of dictionaries
so you can unpack the group object directly in a loop, e.g.
``{% for grouper, list in regrouped %}``.
Tests
~~~~~

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@ -100,3 +100,22 @@ class RegroupTagTests(SimpleTestCase):
def test_regroup08(self):
with self.assertRaises(TemplateSyntaxError):
self.engine.get_template('regroup08')
@setup({'regroup_unpack': '{% regroup data by bar as grouped %}'
'{% for grouper, group in grouped %}'
'{{ grouper }}:'
'{% for item in group %}'
'{{ item.foo }}'
'{% endfor %},'
'{% endfor %}'})
def test_regroup_unpack(self):
output = self.engine.render_to_string('regroup_unpack', {
'data': [
{'foo': 'c', 'bar': 1},
{'foo': 'd', 'bar': 1},
{'foo': 'a', 'bar': 2},
{'foo': 'b', 'bar': 2},
{'foo': 'x', 'bar': 3},
],
})
self.assertEqual(output, '1:cd,2:ab,3:x,')