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

   1 {
   2  "cells": [
   3   {
   4    "cell_type": "markdown",
   5    "metadata": {},
   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     "db61bb90 769 Morgantown 3\n",
  23     "202c898b5f 1284 Morgantown 21\n",
  24     "def36ffcd 1514 Giessenmestia 21\n",
  25     "389018bd0707 1052 Estacada 21\n",
  26     "a487c4270 782 Geoje-Si 14\n",
  27     "6caf2584a55 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 trips to Estacada, Geoje-Si and Stonnington-Island, and the three-day trip to Morgantown. \n",
  40     "\n",
  41     "The 21 day trip to Morgantown and the trips to  Giessenmestia and Nordkapp are all too expensive."
  42    ]
  43   },
  44   {
  45    "cell_type": "markdown",
  46    "metadata": {},
  47    "source": [
  48     "### Solution"
  49    ]
  50   },
  51   {
  52    "cell_type": "code",
  53    "execution_count": 1,
  54    "metadata": {},
  55    "outputs": [
  56     {
  57      "data": {
  58       "text/plain": [
  59        "[['07ea553e', '1348', 'Zhangye-Shi', '14'],\n",
  60        " ['02d4b258b8a', '1152', 'Estacada', '3'],\n",
  61        " ['d29a0551504e', '1210', 'Zhangye-Shi', '7']]"
  62       ]
  63      },
  64      "execution_count": 1,
  65      "metadata": {},
  66      "output_type": "execute_result"
  67     }
  68    ],
  69    "source": [
  70     "holidays = []\n",
  71     "with open('01-holidays.txt') as f:\n",
  72     "    for hol_line in f.readlines():\n",
  73     "        holidays.append(hol_line.split())\n",
  74     "        \n",
  75     "holidays[:3]"
  76    ]
  77   },
  78   {
  79    "cell_type": "code",
  80    "execution_count": 2,
  81    "metadata": {},
  82    "outputs": [
  83     {
  84      "data": {
  85       "text/plain": [
  86        "66"
  87       ]
  88      },
  89      "execution_count": 2,
  90      "metadata": {},
  91      "output_type": "execute_result"
  92     }
  93    ],
  94    "source": [
  95     "affordable_holidays = []\n",
  96     "for h in holidays:\n",
  97     "    if int(h[1]) <= 1200:\n",
  98     "        affordable_holidays.append(h)\n",
  99     "\n",
 100     "len(affordable_holidays)"
 101    ]
 102   },
 103   {
 104    "cell_type": "markdown",
 105    "metadata": {},
 106    "source": [
 107     "### Smart-alec one-line solution"
 108    ]
 109   },
 110   {
 111    "cell_type": "code",
 112    "execution_count": 3,
 113    "metadata": {},
 114    "outputs": [
 115     {
 116      "data": {
 117       "text/plain": [
 118        "66"
 119       ]
 120      },
 121      "execution_count": 3,
 122      "metadata": {},
 123      "output_type": "execute_result"
 124     }
 125    ],
 126    "source": [
 127     "sum(1 for h in open('01-holidays.txt').readlines() if int(h.split()[1]) <= 1200)"
 128    ]
 129   },
 130   {
 131    "cell_type": "markdown",
 132    "metadata": {},
 133    "source": [
 134     "# Part 2\n",
 135     "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",
 136     "\n",
 137     "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",
 138     "\n",
 139     "Assume all holidays have a relative value of 1, apart from these destinations.\n",
 140     "\n",
 141     "| Destination | Score |\n",
 142     "|-------------|-------|\n",
 143     "| Almaty | 2.0 |\n",
 144     "| Brorfelde | 0.9 |\n",
 145     "| Estacada | 0.4 |\n",
 146     "| Jayuya | 0.6 |\n",
 147     "| Karlukovo | 2.2 |\n",
 148     "| Morgantown | 2.9 |\n",
 149     "| Nordkapp | 1.5 |\n",
 150     "| Nullarbor | 2.2 |\n",
 151     "| Puente-Laguna-Garzonkuala-Penyu | 0.4 |\n",
 152     "| Uzupis | 0.9 |\n",
 153     "\n",
 154     "## Example\n",
 155     "\n",
 156     "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. \n",
 157     "\n",
 158     "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",
 159     "\n",
 160     "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",
 161     "\n",
 162     "The best value affordable holiday is the trip to Stonnington Island, with $\\frac{14}{1284} = 0.0193$ nights per pound."
 163    ]
 164   },
 165   {
 166    "cell_type": "code",
 167    "execution_count": 4,
 168    "metadata": {
 169     "collapsed": true
 170    },
 171    "outputs": [],
 172    "source": [
 173     "destination_values = {'Almaty': 2.0, 'Brorfelde': 0.9, 'Estacada': 0.4, 'Jayuya': 0.6, 'Karlukovo': 2.2, \n",
 174     "                      'Morgantown': 2.9,'Nordkapp': 1.5, 'Nullarbor': 2.2, \n",
 175     "                      'Puente-Laguna-Garzonkuala-Penyu': 0.4, 'Uzupis': 0.9}"
 176    ]
 177   },
 178   {
 179    "cell_type": "code",
 180    "execution_count": 5,
 181    "metadata": {
 182     "collapsed": true
 183    },
 184    "outputs": [],
 185    "source": [
 186     "def value_of_destination(name):\n",
 187     "    if name in destination_values:\n",
 188     "        return destination_values[name]\n",
 189     "    else:\n",
 190     "        return 1"
 191    ]
 192   },
 193   {
 194    "cell_type": "code",
 195    "execution_count": 6,
 196    "metadata": {
 197     "collapsed": true
 198    },
 199    "outputs": [],
 200    "source": [
 201     "def value_of_holiday(holiday):\n",
 202     "    hid, cost, destination, duration = tuple(holiday)\n",
 203     "    value = value_of_destination(destination) * float(duration) / int(cost)\n",
 204     "    return value"
 205    ]
 206   },
 207   {
 208    "cell_type": "code",
 209    "execution_count": 7,
 210    "metadata": {},
 211    "outputs": [
 212     {
 213      "data": {
 214       "text/plain": [
 215        "'cb24efd90'"
 216       ]
 217      },
 218      "execution_count": 7,
 219      "metadata": {},
 220      "output_type": "execute_result"
 221     }
 222    ],
 223    "source": [
 224     "best_holiday = ''\n",
 225     "best_value = 0\n",
 226     "\n",
 227     "for h in affordable_holidays:\n",
 228     "    if value_of_holiday(h) > best_value:\n",
 229     "        best_value = value_of_holiday(h)\n",
 230     "        best_holiday = h[0]\n",
 231     "        \n",
 232     "best_holiday"
 233    ]
 234   },
 235   {
 236    "cell_type": "markdown",
 237    "metadata": {},
 238    "source": [
 239     "## Smart-alec solution"
 240    ]
 241   },
 242   {
 243    "cell_type": "code",
 244    "execution_count": 8,
 245    "metadata": {},
 246    "outputs": [
 247     {
 248      "data": {
 249       "text/plain": [
 250        "'cb24efd90'"
 251       ]
 252      },
 253      "execution_count": 8,
 254      "metadata": {},
 255      "output_type": "execute_result"
 256     }
 257    ],
 258    "source": [
 259     "max(affordable_holidays, key=value_of_holiday)[0]"
 260    ]
 261   },
 262   {
 263    "cell_type": "code",
 264    "execution_count": null,
 265    "metadata": {
 266     "collapsed": true
 267    },
 268    "outputs": [],
 269    "source": []
 270   }
 271  ],
 272  "metadata": {
 273   "kernelspec": {
 274    "display_name": "Python 3",
 275    "language": "python",
 276    "name": "python3"
 277   },
 278   "language_info": {
 279    "codemirror_mode": {
 280     "name": "ipython",
 281     "version": 3
 282    },
 283    "file_extension": ".py",
 284    "mimetype": "text/x-python",
 285    "name": "python",
 286    "nbconvert_exporter": "python",
 287    "pygments_lexer": "ipython3",
 288    "version": "3.5.2+"
 289   }
 290  },
 291  "nbformat": 4,
 292  "nbformat_minor": 2
 293 }