exemples.ipynb: Add DataFrame.groupby.expanding.apply

docs/examples.ipynb

@@ -285,6 +285,54 @@
     "res.equals(res_parallel)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# DataFrame.groupby.expanding.apply"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "df_size = int(1e6)\n",
+    "df = pd.DataFrame(dict(a=np.random.randint(1, 300, df_size),\n",
+    "                       b=np.random.rand(df_size)))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def func(x):\n",
+    "    return x.iloc[0] + x.iloc[1] ** 2 + x.iloc[2] ** 3 + x.iloc[3] ** 4"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "%%time\n",
+    "res = df.groupby('a').b.expanding(4).apply(func, raw=False)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "%%time\n",
+    "res_parallel = df.groupby('a').b.expanding(4).parallel_apply(func, raw=False)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},