Drop Python 2 (woohoo!) and import matplotlib as mpl

09_unsupervised_learning.ipynb

@@ -20,7 +20,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "First, let's make sure this notebook works well in both python 2 and 3, import a few common modules, ensure MatplotLib plots figures inline and prepare a function to save the figures:"
+    "First, let's import a few common modules, ensure MatplotLib plots figures inline and prepare a function to save the figures. We also check that Python 3.5 or later is installed (although Python 2.x may work, it is deprecated so we strongly recommend you use Python 3 instead)."
    ]
   },
   {
@@ -29,8 +29,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# To support both python 2 and python 3\n",
-    "from __future__ import division, print_function, unicode_literals\n",
+    "# Python ≥3.5 is required\n",
+    "import sys\n",
+    "assert sys.version_info >= (3, 5)\n",
     "\n",
     "# Common imports\n",
     "import numpy as np\n",
@@ -41,11 +42,11 @@
     "\n",
     "# To plot pretty figures\n",
     "%matplotlib inline\n",
-    "import matplotlib\n",
+    "import matplotlib as mpl\n",
     "import matplotlib.pyplot as plt\n",
-    "plt.rcParams['axes.labelsize'] = 14\n",
-    "plt.rcParams['xtick.labelsize'] = 12\n",
-    "plt.rcParams['ytick.labelsize'] = 12\n",
+    "mpl.rc('axes', labelsize=14)\n",
+    "mpl.rc('xtick', labelsize=12)\n",
+    "mpl.rc('ytick', labelsize=12)\n",
     "\n",
     "# Where to save the figures\n",
     "PROJECT_ROOT_DIR = \".\"\n",
@@ -1337,7 +1338,7 @@
     "        coeffs = silhouette_coefficients[y_pred == i]\n",
     "        coeffs.sort()\n",
     "\n",
-    "        color = matplotlib.cm.Spectral(i / k)\n",
+    "        color = mpl.cm.Spectral(i / k)\n",
     "        plt.fill_betweenx(np.arange(pos, pos + len(coeffs)), 0, coeffs,\n",
     "                          facecolor=color, edgecolor=color, alpha=0.7)\n",
     "        ticks.append(pos + len(coeffs) // 2)\n",