Merge pull request #1564 from pallets/feature/pairs

Added items filter

3 files changed, 43 insertions, 0 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 3e8b56e..8c041f6 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -30,6 +30,7 @@ Unreleased
     :pr:`1571`
 -   Filters and tests decorated with ``@async_variant`` are pickleable.
     :pr:`1612`
+-   Add ``items`` filter. :issue:`1561`
 
 
 Version 3.0.3
diff --git a/src/jinja2/filters.py b/src/jinja2/filters.py
index 9ebd991..80ea650 100644
--- a/src/jinja2/filters.py
+++ b/src/jinja2/filters.py
@@ -218,6 +218,36 @@ def do_lower(s: str) -> str:
     return soft_str(s).lower()
 
 
+def do_items(value: t.Union[t.Mapping[K, V], Undefined]) -> t.Iterator[t.Tuple[K, V]]:
+    """Return an iterator over the ``(key, value)`` items of a mapping.
+
+    ``x|items`` is the same as ``x.items()``, except if ``x`` is
+    undefined an empty iterator is returned.
+
+    This filter is useful if you expect the template to be rendered with
+    an implementation of Jinja in another programming language that does
+    not have a ``.items()`` method on its mapping type.
+
+    .. code-block:: html+jinja
+
+        <dl>
+        {% for key, value in my_dict|items %}
+            <dt>{{ key }}
+            <dd>{{ value }}
+        {% endfor %}
+        </dl>
+
+    .. versionadded:: 3.1
+    """
+    if isinstance(value, Undefined):
+        return
+
+    if not isinstance(value, abc.Mapping):
+        raise TypeError("Can only get item pairs from a mapping.")
+
+    yield from value.items()
+
+
 @pass_eval_context
 def do_xmlattr(
     eval_ctx: "EvalContext", d: t.Mapping[str, t.Any], autospace: bool = True
@@ -1739,6 +1769,7 @@ FILTERS = {
     "length": len,
     "list": do_list,
     "lower": do_lower,
+    "items": do_items,
     "map": do_map,
     "min": do_min,
     "max": do_max,
diff --git a/tests/test_filters.py b/tests/test_filters.py
index 2195157..43ddf59 100644
--- a/tests/test_filters.py
+++ b/tests/test_filters.py
@@ -251,6 +251,17 @@ class TestFilter:
         out = tmpl.render()
         assert out == "foo"
 
+    def test_items(self, env):
+        d = {i: c for i, c in enumerate("abc")}
+        tmpl = env.from_string("""{{ d|items|list }}""")
+        out = tmpl.render(d=d)
+        assert out == "[(0, 'a'), (1, 'b'), (2, 'c')]"
+
+    def test_items_undefined(self, env):
+        tmpl = env.from_string("""{{ d|items|list }}""")
+        out = tmpl.render()
+        assert out == "[]"
+
     def test_pprint(self, env):
         from pprint import pformat