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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
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commit 16269c4d0a5d2e61c7555fec438440abee9be9f5 1 parent 83fe33e
@freakboy3742 freakboy3742 authored
View
56 django/template/defaulttags.py
@@ -5,6 +5,7 @@
from django.template import get_library, Library, InvalidTemplateLibrary
from django.conf import settings
import sys
+import re
register = Library()
@@ -61,8 +62,8 @@ def render(self, context):
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 @@ def __repr__(self):
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 @@ def reverse(data):
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 @@ def reverse(data):
'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):
@@ -530,8 +543,14 @@ 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):
View
22 docs/templates.txt
@@ -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:
View
14 tests/regressiontests/templates/tests.py
@@ -289,6 +289,20 @@ def test_templates(self):
'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"),
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