add loading example

docs/tutorials/loading_data.ipynb

@@ -6,11 +6,72 @@
    "source": [
     "# Loading Data into Nested-Dask"
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import nested_pandas as npd\n",
+    "import nested_dask as nd"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## From Nested-Pandas\n",
+    "\n",
+    "Nested-Dask can load data from Nested-Pandas `NestedFrame` objects by using the `from_nested_pandas` class function."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Create a Nested-Pandas NestedFrame\n",
+    "nf = npd.NestedFrame(data={\"a\": [1, 2, 3], \"b\": [2, 4, 6]}, index=[0, 1, 2])\n",
+    "\n",
+    "nested = npd.NestedFrame(\n",
+    "    data={\"c\": [0, 2, 4, 1, 4, 3, 1, 4, 1], \"d\": [5, 4, 7, 5, 3, 1, 9, 3, 4]},\n",
+    "    index=[0, 0, 0, 1, 1, 1, 2, 2, 2],\n",
+    ")\n",
+    "\n",
+    "nf = nf.add_nested(nested, \"nested\")\n",
+    "\n",
+    "# Convert to Nested-Dask NestedFrame\n",
+    "nf = nd.NestedFrame.from_nested_pandas(nf)\n",
+    "nf"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Loading from Parquet Files"
+   ]
   }
  ],
  "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
   "language_info": {
-   "name": "python"
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.11"
   }
  },
  "nbformat": 4,