fixes #716

Author: jph00

fastcore/_modidx.py

@@ -401,6 +401,7 @@
                                      'fastcore.foundation.L.zipwith': ('foundation.html#l.zipwith', 'fastcore/foundation.py'),
                                      'fastcore.foundation._L_Meta': ('foundation.html#_l_meta', 'fastcore/foundation.py'),
                                      'fastcore.foundation._L_Meta.__call__': ('foundation.html#_l_meta.__call__', 'fastcore/foundation.py'),
+                                     'fastcore.foundation._batched': ('foundation.html#_batched', 'fastcore/foundation.py'),
                                      'fastcore.foundation._f': ('foundation.html#_f', 'fastcore/foundation.py'),
                                      'fastcore.foundation.add_docs': ('foundation.html#add_docs', 'fastcore/foundation.py'),
                                      'fastcore.foundation.coll_repr': ('foundation.html#coll_repr', 'fastcore/foundation.py'),

fastcore/foundation.py

@@ -479,11 +479,23 @@ def pairwise(self:L):
     "Same as `itertools.pairwise`"
     return self._new(itertools.pairwise(self))
 
+# %% ../nbs/02_foundation.ipynb
+def _batched(iterable, n):
+    "Batch data into tuples of length n. The last batch may be shorter."
+    if n < 1: raise ValueError('n must be at least one')
+    it = iter(iterable)
+    while batch := tuple(itertools.islice(it, n)):
+        yield batch
+
+# %% ../nbs/02_foundation.ipynb
+try: from itertools import batched
+except ImportError: batched = _batched
+
 # %% ../nbs/02_foundation.ipynb
 @patch
 def batched(self:L, n):
     "Same as `itertools.batched`"
-    return self._new(itertools.batched(self, n))
+    return self._new(batched(self, n))
 
 # %% ../nbs/02_foundation.ipynb
 @patch

nbs/02_foundation.ipynb

@@ -2672,15 +2672,43 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "c5984ee1",
+   "id": "1f2a370c",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#| export\n",
+    "def _batched(iterable, n):\n",
+    "    \"Batch data into tuples of length n. The last batch may be shorter.\"\n",
+    "    if n < 1: raise ValueError('n must be at least one')\n",
+    "    it = iter(iterable)\n",
+    "    while batch := tuple(itertools.islice(it, n)):\n",
+    "        yield batch"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "41aefe58",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#| export\n",
+    "try: from itertools import batched\n",
+    "except ImportError: batched = _batched"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "d9f7ffb9",
    "metadata": {},
    "outputs": [],
    "source": [
     "#| export\n",
     "@patch\n",
     "def batched(self:L, n):\n",
     "    \"Same as `itertools.batched`\"\n",
-    "    return self._new(itertools.batched(self, n))"
+    "    return self._new(batched(self, n))"
    ]
   },
   {
@@ -2952,6 +2980,14 @@
     "test_eq(L([1,2,3]).flatten(), [1,2,3])  # already flat"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "88fa0ef8",
+   "metadata": {},
+   "source": [
+    "##### User"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "8cf19e29",