Added bonus question to the DIY on slicing

ipynb/pres02_basic_statements.ipynb

@@ -1051,7 +1051,8 @@
     "- Extract the first field (e.g. using `find` method and slicing)\n",
     "- Extract the last field (e.g. using `rfind` method and slicing)\n",
     "- Check for empty field (e.g. `find` \";;\" pattern)\n",
-    "- Remove empty field (e.g. using replace method)"
+    "- Remove empty field (e.g. using replace method)\n",
+    "- BONUS : Extract the second field (tip :`find` can take an argument that tells where to start the search)"
    ]
   },
   {
@@ -1067,7 +1068,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 32,
+   "execution_count": 12,
    "metadata": {},
    "outputs": [
     {
@@ -1076,6 +1077,7 @@
      "text": [
       "--wind;temperature;;pressure--\n",
       "wind\n",
+      "temperature\n",
       "pressure\n",
       "16\n",
       "wind;temperature;pressure\n"
@@ -1091,10 +1093,14 @@
     "idx = s.find(\";\")\n",
     "s0 = s[0:idx]\n",
     "print(s0)\n",
-    "# extract the last field\n",
-    "idx = s.rfind(\";\")\n",
-    "s1 = s[idx+1:]\n",
+    "# extract the second field\n",
+    "idx1 = s.find(\";\", idx+1) # start the search after the first \";\"\n",
+    "s1 = s[idx+1:idx1]\n",
     "print(s1)\n",
+    "# extract the last field\n",
+    "idx2 = s.rfind(\";\")\n",
+    "s2 = s[idx2+1:]\n",
+    "print(s2)\n",
     "idx_first_empty_field = s.find(\";;\")\n",
     "print(idx_first_empty_field)\n",
     "# remove empty field\n",