aboutsummaryrefslogtreecommitdiffhomepage
path: root/vendor/twig/twig/doc/tags/for.rst
diff options
context:
space:
mode:
Diffstat (limited to 'vendor/twig/twig/doc/tags/for.rst')
-rw-r--r--vendor/twig/twig/doc/tags/for.rst172
1 files changed, 172 insertions, 0 deletions
diff --git a/vendor/twig/twig/doc/tags/for.rst b/vendor/twig/twig/doc/tags/for.rst
new file mode 100644
index 00000000..0673b551
--- /dev/null
+++ b/vendor/twig/twig/doc/tags/for.rst
@@ -0,0 +1,172 @@
1``for``
2=======
3
4Loop over each item in a sequence. For example, to display a list of users
5provided in a variable called ``users``:
6
7.. code-block:: jinja
8
9 <h1>Members</h1>
10 <ul>
11 {% for user in users %}
12 <li>{{ user.username|e }}</li>
13 {% endfor %}
14 </ul>
15
16.. note::
17
18 A sequence can be either an array or an object implementing the
19 ``Traversable`` interface.
20
21If you do need to iterate over a sequence of numbers, you can use the ``..``
22operator:
23
24.. code-block:: jinja
25
26 {% for i in 0..10 %}
27 * {{ i }}
28 {% endfor %}
29
30The above snippet of code would print all numbers from 0 to 10.
31
32It can be also useful with letters:
33
34.. code-block:: jinja
35
36 {% for letter in 'a'..'z' %}
37 * {{ letter }}
38 {% endfor %}
39
40The ``..`` operator can take any expression at both sides:
41
42.. code-block:: jinja
43
44 {% for letter in 'a'|upper..'z'|upper %}
45 * {{ letter }}
46 {% endfor %}
47
48.. tip:
49
50 If you need a step different from 1, you can use the ``range`` function
51 instead.
52
53The `loop` variable
54-------------------
55
56Inside of a ``for`` loop block you can access some special variables:
57
58===================== =============================================================
59Variable Description
60===================== =============================================================
61``loop.index`` The current iteration of the loop. (1 indexed)
62``loop.index0`` The current iteration of the loop. (0 indexed)
63``loop.revindex`` The number of iterations from the end of the loop (1 indexed)
64``loop.revindex0`` The number of iterations from the end of the loop (0 indexed)
65``loop.first`` True if first iteration
66``loop.last`` True if last iteration
67``loop.length`` The number of items in the sequence
68``loop.parent`` The parent context
69===================== =============================================================
70
71.. code-block:: jinja
72
73 {% for user in users %}
74 {{ loop.index }} - {{ user.username }}
75 {% endfor %}
76
77.. note::
78
79 The ``loop.length``, ``loop.revindex``, ``loop.revindex0``, and
80 ``loop.last`` variables are only available for PHP arrays, or objects that
81 implement the ``Countable`` interface. They are also not available when
82 looping with a condition.
83
84.. versionadded:: 1.2
85 The ``if`` modifier support has been added in Twig 1.2.
86
87Adding a condition
88------------------
89
90Unlike in PHP, it's not possible to ``break`` or ``continue`` in a loop. You
91can however filter the sequence during iteration which allows you to skip
92items. The following example skips all the users which are not active:
93
94.. code-block:: jinja
95
96 <ul>
97 {% for user in users if user.active %}
98 <li>{{ user.username|e }}</li>
99 {% endfor %}
100 </ul>
101
102The advantage is that the special loop variable will count correctly thus not
103counting the users not iterated over. Keep in mind that properties like
104``loop.last`` will not be defined when using loop conditions.
105
106.. note::
107
108 Using the ``loop`` variable within the condition is not recommended as it
109 will probably not be doing what you expect it to. For instance, adding a
110 condition like ``loop.index > 4`` won't work as the index is only
111 incremented when the condition is true (so the condition will never
112 match).
113
114The `else` Clause
115-----------------
116
117If no iteration took place because the sequence was empty, you can render a
118replacement block by using ``else``:
119
120.. code-block:: jinja
121
122 <ul>
123 {% for user in users %}
124 <li>{{ user.username|e }}</li>
125 {% else %}
126 <li><em>no user found</em></li>
127 {% endfor %}
128 </ul>
129
130Iterating over Keys
131-------------------
132
133By default, a loop iterates over the values of the sequence. You can iterate
134on keys by using the ``keys`` filter:
135
136.. code-block:: jinja
137
138 <h1>Members</h1>
139 <ul>
140 {% for key in users|keys %}
141 <li>{{ key }}</li>
142 {% endfor %}
143 </ul>
144
145Iterating over Keys and Values
146------------------------------
147
148You can also access both keys and values:
149
150.. code-block:: jinja
151
152 <h1>Members</h1>
153 <ul>
154 {% for key, user in users %}
155 <li>{{ key }}: {{ user.username|e }}</li>
156 {% endfor %}
157 </ul>
158
159Iterating over a Subset
160-----------------------
161
162You might want to iterate over a subset of values. This can be achieved using
163the :doc:`slice <../filters/slice>` filter:
164
165.. code-block:: jinja
166
167 <h1>Top Ten Members</h1>
168 <ul>
169 {% for user in users|slice(0, 10) %}
170 <li>{{ user.username|e }}</li>
171 {% endfor %}
172 </ul>