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Fixed #3523 -- Added list unpacking to for loops in templates. Thanks to SmileyChris and Honza Kral for their work. 

git-svn-id: http://code.djangoproject.com/svn/django/trunk@5443 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee 2007-06-08 11:58:03 +00:00
parent 83fe33e277
commit 16269c4d0a
3 changed files with 74 additions and 18 deletions
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56
django/template/defaulttags.py
View File

@ -5,6 +5,7 @@ from django.template import TemplateSyntaxError, VariableDoesNotExist, BLOCK_TAG
from django.template import get_library, Library, InvalidTemplateLibrary
from django.conf import settings
import sys
import re
register = Library()
@ -61,8 +62,8 @@ class FirstOfNode(Node):
return ''
class ForNode(Node):
def __init__(self, loopvar, sequence, reversed, nodelist_loop):
self.loopvar, self.sequence = loopvar, sequence
def __init__(self, loopvars, sequence, reversed, nodelist_loop):
self.loopvars, self.sequence = loopvars, sequence
self.reversed = reversed
self.nodelist_loop = nodelist_loop
@ -72,7 +73,7 @@ class ForNode(Node):
else:
reversed = ''
return "<For Node: for %s in %s, tail_len: %d%s>" % \
(self.loopvar, self.sequence, len(self.nodelist_loop), reversed)
(', '.join( self.loopvars ), self.sequence, len(self.nodelist_loop), reversed)
def __iter__(self):
for node in self.nodelist_loop:
@ -107,6 +108,7 @@ class ForNode(Node):
for index in range(len(data)-1, -1, -1):
yield data[index]
values = reverse(values)
unpack = len(self.loopvars) > 1
for i, item in enumerate(values):
context['forloop'] = {
# shortcuts for current loop iteration number
@ -120,9 +122,20 @@ class ForNode(Node):
'last': (i == len_values - 1),
'parentloop': parentloop,
}
context[self.loopvar] = item
if unpack:
# If there are multiple loop variables, unpack the item into them.
context.update(dict(zip(self.loopvars, item)))
else:
context[self.loopvars[0]] = item
for node in self.nodelist_loop:
nodelist.append(node.render(context))
if unpack:
# The loop variables were pushed on to the context so pop them
# off again. This is necessary because the tag lets the length
# of loopvars differ to the length of each set of items and we
# don't want to leave any vars from the previous loop on the
# context.
context.pop()
context.pop()
return nodelist.render(context)
@ -486,7 +499,7 @@ def do_filter(parser, token):
nodelist = parser.parse(('endfilter',))
parser.delete_first_token()
return FilterNode(filter_expr, nodelist)
filter = register.tag("filter", do_filter)
do_filter = register.tag("filter", do_filter)
#@register.tag
def firstof(parser, token):
@ -530,9 +543,15 @@ def do_for(parser, token):
{% endfor %}
</ul>
You can also loop over a list in reverse by using
You can loop over a list in reverse by using
``{% for obj in list reversed %}``.
You can also unpack multiple values from a two-dimensional array::
{% for key,value in dict.items %}
{{ key }}: {{ value }}
{% endfor %}
The for loop sets a number of variables available within the loop:
========================== ================================================
@ -552,18 +571,23 @@ def do_for(parser, token):
"""
bits = token.contents.split()
if len(bits) == 5 and bits[4] != 'reversed':
raise TemplateSyntaxError, "'for' statements with five words should end in 'reversed': %s" % token.contents
if len(bits) not in (4, 5):
raise TemplateSyntaxError, "'for' statements should have either four or five words: %s" % token.contents
if bits[2] != 'in':
raise TemplateSyntaxError, "'for' statement must contain 'in' as the second word: %s" % token.contents
loopvar = bits[1]
sequence = parser.compile_filter(bits[3])
reversed = (len(bits) == 5)
if len(bits) < 4:
raise TemplateSyntaxError, "'for' statements should have at least four words: %s" % token.contents
reversed = bits[-1] == 'reversed'
in_index = reversed and -3 or -2
if bits[in_index] != 'in':
raise TemplateSyntaxError, "'for' statements should use the format 'for x in y': %s" % token.contents
loopvars = re.sub(r' *, *', ',', ' '.join(bits[1:in_index])).split(',')
for var in loopvars:
if not var or ' ' in var:
raise TemplateSyntaxError, "'for' tag received an invalid argument: %s" % token.contents
sequence = parser.compile_filter(bits[in_index+1])
nodelist_loop = parser.parse(('endfor',))
parser.delete_first_token()
return ForNode(loopvar, sequence, reversed, nodelist_loop)
return ForNode(loopvars, sequence, reversed, nodelist_loop)
do_for = register.tag("for", do_for)
def do_ifequal(parser, token, negate):

22
docs/templates.txt
View File

@ -447,7 +447,7 @@ for
~~~
Loop over each item in an array. For example, to display a list of athletes
given ``athlete_list``::
provided in ``athlete_list``::
<ul>
{% for athlete in athlete_list %}
@ -455,7 +455,25 @@ given ``athlete_list``::
{% endfor %}
</ul>
You can also loop over a list in reverse by using ``{% for obj in list reversed %}``.
You can loop over a list in reverse by using ``{% for obj in list reversed %}``.
**New in Django development version**
If you need to loop over a list of lists, you can unpack the values
in eachs sub-list into a set of known names. For example, if your context contains
a list of (x,y) coordinates called ``points``, you could use the following
to output the list of points::
{% for x, y in points %}
There is a point at {{ x }},{{ y }}
{% endfor %}
This can also be useful if you need to access the items in a dictionary.
For example, if your context contained a dictionary ``data``, the following
would display the keys and values of the dictionary::
{% for key, value in data.items %}
{{ key }}: {{ value }}
{% endfor %}
The for loop sets a number of variables available within the loop:

14
tests/regressiontests/templates/tests.py
View File

@ -289,6 +289,20 @@ class Templates(unittest.TestCase):
'for-tag-vars02': ("{% for val in values %}{{ forloop.counter0 }}{% endfor %}", {"values": [6, 6, 6]}, "012"),
'for-tag-vars03': ("{% for val in values %}{{ forloop.revcounter }}{% endfor %}", {"values": [6, 6, 6]}, "321"),
'for-tag-vars04': ("{% for val in values %}{{ forloop.revcounter0 }}{% endfor %}", {"values": [6, 6, 6]}, "210"),
'for-tag-unpack01': ("{% for key,value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, "one:1/two:2/"),
'for-tag-unpack03': ("{% for key, value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, "one:1/two:2/"),
'for-tag-unpack04': ("{% for key , value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, "one:1/two:2/"),
'for-tag-unpack05': ("{% for key ,value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, "one:1/two:2/"),
'for-tag-unpack06': ("{% for key value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, template.TemplateSyntaxError),
'for-tag-unpack07': ("{% for key,,value in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, template.TemplateSyntaxError),
'for-tag-unpack08': ("{% for key,value, in items %}{{ key }}:{{ value }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, template.TemplateSyntaxError),
# Ensure that a single loopvar doesn't truncate the list in val.
'for-tag-unpack09': ("{% for val in items %}{{ val.0 }}:{{ val.1 }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, "one:1/two:2/"),
# Otherwise, silently truncate if the length of loopvars differs to the length of each set of items.
'for-tag-unpack10': ("{% for x,y in items %}{{ x }}:{{ y }}/{% endfor %}", {"items": (('one', 1, 'carrot'), ('two', 2, 'orange'))}, "one:1/two:2/"),
'for-tag-unpack11': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, ("one:1,/two:2,/", "one:1,INVALID/two:2,INVALID/")),
'for-tag-unpack12': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1, 'carrot'), ('two', 2))}, ("one:1,carrot/two:2,/", "one:1,carrot/two:2,INVALID/")),
'for-tag-unpack13': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1, 'carrot'), ('two', 2, 'cheese'))}, ("one:1,carrot/two:2,cheese/", "one:1,carrot/two:2,cheese/")),
### IF TAG ################################################################
'if-tag01': ("{% if foo %}yes{% else %}no{% endif %}", {"foo": True}, "yes"),