Input now downloads file from github

ipynb/Advent 2017.ipynb

@@ -38,6 +38,9 @@
     "%matplotlib inline\n",
     "import matplotlib.pyplot as plt\n",
     "\n",
+    "import os\n",
+    "import urllib.request\n",
+    "\n",
     "import re\n",
     "import numpy as np\n",
     "import math\n",
@@ -65,7 +68,16 @@
     "\n",
     "def Input(day, year=2017):\n",
     "    \"Open this day's input file.\"\n",
-    "    return open('data/advent{}/input{}.txt'.format(year, day))\n",
+    "    directory = 'advent{}/'.format(year)\n",
+    "    filename = directory+'input{}.txt'.format(day)\n",
+    "    try:\n",
+    "        return open(filename)\n",
+    "    except FileNotFoundError:\n",
+    "        if not os.path.exists(directory):\n",
+    "            os.makedirs(directory)\n",
+    "\n",
+    "        urllib.request.urlretrieve(\"https://raw.githubusercontent.com/norvig/pytudes/master/data/\" + filename, filename)\n",
+    "        return Input(day)\n",
     "    \n",
     "def array(lines):\n",
     "    \"Parse an iterable of str lines into a 2-D array. If `lines` is a str, splitlines.\"\n",