alt solution to one hot encoding

intro-neural-networks/student-admissions/StudentAdmissionsSolutions.ipynb

@@ -22,6 +22,7 @@
    },
    "outputs": [],
    "source": [
+    "## One solution\n",
     "# Make dummy variables for rank\n",
     "one_hot_data = pd.concat([data, pd.get_dummies(data['rank'], prefix='rank')], axis=1)\n",
     "\n",
@@ -32,6 +33,22 @@
     "one_hot_data[:10]"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": [
+    "## Alternative solution ##\n",
+    "# if you're using an up-to-date version of pandas, \n",
+    "# you can also use selection by columns\n",
+    "\n",
+    "# an equally valid solution\n",
+    "one_hot_data = pd.get_dummies(data, columns=['rank'])"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -83,7 +100,7 @@
    },
    "outputs": [],
    "source": [
-    "## alternative solution ##\n",
+    "## Alternative solution ##\n",
     "# you could also *only* use y and the output \n",
     "# and calculate sigmoid_prime directly from the activated output!\n",
     "\n",