01-ticket-prices/ticket-pricing-solution.ipynb

   1 {
   2  "cells": [
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   4    "cell_type": "markdown",
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   6    "source": [
   7     "# Ticket pricing\n",
   8     "\n",
   9     "You've been shopping around for a holiday package deal and its time to make your choice of which deal to go with. The file [01-holidays.txt](01-holidays.txt) contains a summary of your investigations. \n",
  10     "\n",
  11     "It's a simple text file, with one possible holiday package per line.\n",
  12     "\n",
  13     "Each line has four fields, separated by spaces. They are:\n",
  14     "* The deal ID, from the price comparison website you found it.\n",
  15     "* The holiday price, in whole pounds.\n",
  16     "* The location of the holiday, always a single word.\n",
  17     "* The number of nights you'd be staying. \n",
  18     "\n",
  19     "For example, the data file might look like this:\n",
  20     "\n",
  21     "```\n",
  22     "db61bb906d 769 Morgantown 3\n",
  23     "202c898b5f 1284 Morgantown 21\n",
  24     "def36ffc7d 1514 Giessenmestia 21\n",
  25     "389018bd07 1052 Estacada 21\n",
  26     "a487c4270a 782 Geoje-Si 14\n",
  27     "6caf2584a5 724 Stonington-Island 14\n",
  28     "199608abc5 1209 Nordkapp 21\n",
  29     "```"
  30    ]
  31   },
  32   {
  33    "cell_type": "markdown",
  34    "metadata": {},
  35    "source": [
  36     "## Part 1\n",
  37     "You have a budget of £1200. How many of the holidays can you afford?\n",
  38     "\n",
  39     "Given the example data above, you could afford four of the holidays: the 21 day trip to Morgantown and the trips to  Giessenmestia and Nordkapp are all too expensive."
  40    ]
  41   },
  42   {
  43    "cell_type": "markdown",
  44    "metadata": {},
  45    "source": [
  46     "### Solution"
  47    ]
  48   },
  49   {
  50    "cell_type": "code",
  51    "execution_count": 7,
  52    "metadata": {},
  53    "outputs": [
  54     {
  55      "data": {
  56       "text/plain": [
  57        "[['5f12ce1b86', '1192', 'Sukhumi', '14'],\n",
  58        " ['0279c8a91b', '1008', 'Estacada', '14'],\n",
  59        " ['1faea40e9c', '1085', 'Tambon-Pa-Fa', '14']]"
  60       ]
  61      },
  62      "execution_count": 7,
  63      "metadata": {},
  64      "output_type": "execute_result"
  65     }
  66    ],
  67    "source": [
  68     "holidays = []\n",
  69     "with open('01-holidays.txt') as f:\n",
  70     "    for hol_line in f.readlines():\n",
  71     "        holidays.append(hol_line.split())\n",
  72     "        \n",
  73     "holidays[:3]"
  74    ]
  75   },
  76   {
  77    "cell_type": "code",
  78    "execution_count": 25,
  79    "metadata": {},
  80    "outputs": [
  81     {
  82      "data": {
  83       "text/plain": [
  84        "57"
  85       ]
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  87      "execution_count": 25,
  88      "metadata": {},
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  91    ],
  92    "source": [
  93     "affordable_holidays = []\n",
  94     "for h in holidays:\n",
  95     "    if int(h[1]) <= 1200:\n",
  96     "        affordable_holidays.append(h)\n",
  97     "\n",
  98     "len(affordable_holidays)"
  99    ]
 100   },
 101   {
 102    "cell_type": "markdown",
 103    "metadata": {},
 104    "source": [
 105     "### Smart-alec one-line solution"
 106    ]
 107   },
 108   {
 109    "cell_type": "code",
 110    "execution_count": 6,
 111    "metadata": {},
 112    "outputs": [
 113     {
 114      "data": {
 115       "text/plain": [
 116        "57"
 117       ]
 118      },
 119      "execution_count": 6,
 120      "metadata": {},
 121      "output_type": "execute_result"
 122     }
 123    ],
 124    "source": [
 125     "sum(1 for h in open('01-holidays.txt').readlines() if int(h.split()[1]) <= 1200)"
 126    ]
 127   },
 128   {
 129    "cell_type": "markdown",
 130    "metadata": {},
 131    "source": [
 132     "# Part 2\n",
 133     "You don't just want _a_ holiday. You want the _best_ holiday. What is the code of the holiday which would give you the best value?\n",
 134     "\n",
 135     "The \"value\" of a holiday is the duration per pound. Because some destinations are better than others, you'll want to scale the value for some locations. For instance, a night in Timbuktu is worth three times as much as a holiday in Bletchley.\n",
 136     "\n",
 137     "Assume all holidays have a relative value of 1, apart from these destinations.\n",
 138     "\n",
 139     "| Destination | Score |\n",
 140     "|-------------|-------|\n",
 141     "| Almaty | 2.0 |\n",
 142     "| Brorfelde | 0.9 |\n",
 143     "| Estacada | 0.4 |\n",
 144     "| Jayuya | 0.6 |\n",
 145     "| Karlukovo | 2.2 |\n",
 146     "| Morgantown | 2.9 |\n",
 147     "| Nordkapp | 1.5 |\n",
 148     "| Nullarbor | 2.2 |\n",
 149     "| Puente-Laguna-Garzonkuala-Penyu | 0.4 |\n",
 150     "| Uzupis | 0.9 |\n",
 151     "\n",
 152     "## Example\n",
 153     "\n",
 154     "Given the holiday list above, the holiday to Geoje-Si (with the standard weighting of 1) has a value of $\\frac{14}{782} = 0.0179$ nights per pound. The best value holiday is the 21 day trip to Morgantown, with a value of $2.9 \\times \\frac{21}{1284} = 0.0474$ nights per pound. Unfortunately, it's unaffordable. \n",
 155     "\n",
 156     "The trip to Estacada looks promising, at $\\frac{21}{1052} = 0.0200$ nights per pound. Unfortunately, the weighting for Estacada is low, to the adjusted cost is $0.4 \\times \\frac{21}{1052} = 0.00798$ nights per pound.\n",
 157     "\n",
 158     "The best value affordable holiday is the trip to Stonnington Island, with $\\frac{14}{1284} = 0.0193$ nights per pound."
 159    ]
 160   },
 161   {
 162    "cell_type": "code",
 163    "execution_count": 9,
 164    "metadata": {
 165     "collapsed": true
 166    },
 167    "outputs": [],
 168    "source": [
 169     "destination_values = {'Almaty': 2.0, 'Brorfelde': 0.9, 'Estacada': 0.4, 'Jayuya': 0.6, 'Karlukovo': 2.2, \n",
 170     "                      'Morgantown': 2.9,'Nordkapp': 1.5, 'Nullarbor': 2.2, \n",
 171     "                      'Puente-Laguna-Garzonkuala-Penyu': 0.4, 'Uzupis': 0.9}"
 172    ]
 173   },
 174   {
 175    "cell_type": "code",
 176    "execution_count": 11,
 177    "metadata": {},
 178    "outputs": [],
 179    "source": [
 180     "def value_of_destination(name):\n",
 181     "    if name in destination_values:\n",
 182     "        return destination_values[name]\n",
 183     "    else:\n",
 184     "        return 1"
 185    ]
 186   },
 187   {
 188    "cell_type": "code",
 189    "execution_count": 32,
 190    "metadata": {},
 191    "outputs": [],
 192    "source": [
 193     "def value_of_holiday(holiday):\n",
 194     "    hid, cost, destination, duration = tuple(holiday)\n",
 195     "    value = value_of_destination(destination) * float(duration) / int(cost)\n",
 196     "    return value"
 197    ]
 198   },
 199   {
 200    "cell_type": "code",
 201    "execution_count": 36,
 202    "metadata": {},
 203    "outputs": [
 204     {
 205      "data": {
 206       "text/plain": [
 207        "'dc16c9b87f'"
 208       ]
 209      },
 210      "execution_count": 36,
 211      "metadata": {},
 212      "output_type": "execute_result"
 213     }
 214    ],
 215    "source": [
 216     "best_holiday = ''\n",
 217     "best_value = 0\n",
 218     "\n",
 219     "for h in affordable_holidays:\n",
 220     "    if value_of_holiday(h) > best_value:\n",
 221     "        best_value = value_of_holiday(h)\n",
 222     "        best_holiday = h[0]\n",
 223     "        \n",
 224     "best_holiday"
 225    ]
 226   },
 227   {
 228    "cell_type": "markdown",
 229    "metadata": {},
 230    "source": [
 231     "## Smart-alec solution"
 232    ]
 233   },
 234   {
 235    "cell_type": "code",
 236    "execution_count": 34,
 237    "metadata": {},
 238    "outputs": [
 239     {
 240      "data": {
 241       "text/plain": [
 242        "'dc16c9b87f'"
 243       ]
 244      },
 245      "execution_count": 34,
 246      "metadata": {},
 247      "output_type": "execute_result"
 248     }
 249    ],
 250    "source": [
 251     "max(affordable_holidays, key=value_of_holiday)[0]"
 252    ]
 253   },
 254   {
 255    "cell_type": "code",
 256    "execution_count": null,
 257    "metadata": {
 258     "collapsed": true
 259    },
 260    "outputs": [],
 261    "source": []
 262   }
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