{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "searching-meditation",
   "metadata": {},
   "source": [
    "# Class hierarchies, Exceptions and Files (17/3 - 2021)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "outdoor-consultation",
   "metadata": {},
   "source": [
    "## Exercise\n",
    "\n",
    "Create a class ``volume`` to represent a volume.  The calls should have methods ``get_liter``, ``get_imperial_oz``, ``get_us_oz`` to return the volume in liters, imperial fluid ounces, and US fluid ounces.\n",
    "\n",
    "Create a subclass ``container`` of ``volume`` that furthermore has an attribute ``material``."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 59,
   "id": "interesting-program",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "v.get_liter()=0.29569999999999996\n",
      "v.get_us_oz()=9.999999999999998\n",
      "v.get_imperial_oz()=10.408306934178105\n"
     ]
    }
   ],
   "source": [
    "class Volume:\n",
    "    US_OF_IN_LITER = 0.02957\n",
    "    IMPERIAL_OZ_IN_LITER = 0.02841 \n",
    "    \n",
    "    def __init__(self, *, liter=None, us_oz=None, imperial_oz=None):\n",
    "        self._volume = 0  # liter\n",
    "        if liter != None:\n",
    "            self.set_liter(liter)\n",
    "        if us_oz != None:\n",
    "            self.set_us_oz(us_oz)\n",
    "        if imperial_oz != None:\n",
    "            self.set_imperial_oz(imperial_oz)\n",
    "            \n",
    "    def get_liter(self):\n",
    "        return self._volume        \n",
    "        \n",
    "    def get_us_oz(self):\n",
    "        return self._volume / Volume.US_OF_IN_LITER\n",
    "        \n",
    "    def get_imperial_oz(self):\n",
    "        return self._volume / Volume.IMPERIAL_OZ_IN_LITER\n",
    "        \n",
    "    def set_us_oz(self, us_oz):\n",
    "        self._volume = us_oz * Volume.US_OF_IN_LITER\n",
    "\n",
    "    def set_liter(self, liter):\n",
    "        self._volume = liter\n",
    "        \n",
    "    def set_imperial_oz(self, imperial_oz):\n",
    "        self._volume = imperial_oz * Volume.IMPERIAL_OZ_IN_LITER\n",
    "\n",
    "v = Volume(us_oz=10)\n",
    "#v.set_liter(1)\n",
    "print(f'{v.get_liter()=}')\n",
    "print(f'{v.get_us_oz()=}')\n",
    "print(f'{v.get_imperial_oz()=}')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "incomplete-kitchen",
   "metadata": {},
   "outputs": [],
   "source": [
    "class Container(Volume):\n",
    "    def __init__(self, *, material='unknown', liter=None, us_oz=None, imperial_oz=None):\n",
    "        super().__init__(liter=liter, us_oz=us_oz, imperial_oz=imperial_oz)\n",
    "        self.material = material\n",
    "        \n",
    "bottle = Container(material='glass', us_oz=10)\n",
    "#bottle.set_liter(0.25)\n",
    "\n",
    "print(bottle.get_liter())\n",
    "print(bottle.material)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "cloudy-cabinet",
   "metadata": {},
   "source": [
    "## Exercise\n",
    "\n",
    "Create a function ``eval_function(f, values)`` that prints ``f(x)`` for all ``x`` in ``values``. If the function raises an error for a value print \"error\" for this value."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "subject-meeting",
   "metadata": {},
   "outputs": [],
   "source": [
    "def eval_function(f, values):\n",
    "    for x in values:\n",
    "        print(x, '->', f(x))\n",
    "        \n",
    "def square(x):\n",
    "    return x ** 2\n",
    "\n",
    "eval_function(square, [1, 2, 3, 4])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "destroyed-suspension",
   "metadata": {},
   "outputs": [],
   "source": [
    "eval_function(lambda x: x ** 3, [1, 2, 3, 4])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "champion-boxing",
   "metadata": {},
   "outputs": [],
   "source": [
    "def eval_function(f, values):\n",
    "    for x in values:\n",
    "        try:\n",
    "            answer = f(x)\n",
    "        except Exception:\n",
    "            answer = 'error'\n",
    "        print(x, '->', answer)\n",
    "\n",
    "eval_function(lambda x: 1 / x, [-3, -2, -1, 0, 1, 2, 3])"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "meaningful-consultancy",
   "metadata": {},
   "source": [
    "## Exercise\n",
    "\n",
    "Create a function ``create pairs(X, Y)`` that given two lists ``X`` and ``Y`` returns the list of pairs ``[(X[0], Y[0]), (X[1], Y[1]), ...]``. If the two lists have different length, raise a \"ValueError\" exception."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "academic-appointment",
   "metadata": {},
   "outputs": [],
   "source": [
    "def create_pairs(X, Y):\n",
    "    L = []\n",
    "    for i in range(len(X)):\n",
    "        L.append((X[i], Y[i]))\n",
    "    return L\n",
    "\n",
    "print(create_pairs([1, 2, 3], [4, 5, 6]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "id": "nervous-application",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[(1, 4), (2, 5), (3, 6)]\n",
      "[(1, 7), (2, 8)]\n"
     ]
    }
   ],
   "source": [
    "def create_pairs(X, Y):\n",
    "    return list(zip(X, Y))\n",
    "\n",
    "print(create_pairs([1, 2, 3], [4, 5, 6]))\n",
    "print(create_pairs([1, 2, 3], [7, 8]))  # ignores 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "north-volume",
   "metadata": {},
   "outputs": [],
   "source": [
    "def create_pairs(X, Y):\n",
    "    if len(X) != len(Y):\n",
    "        print('X and Y have different lengths')\n",
    "        return None  # will likely cause some problems elsewhere\n",
    "    \n",
    "    return list(zip(X, Y))\n",
    "\n",
    "print(create_pairs([1, 2, 3], [4, 5, 6]))\n",
    "print(create_pairs([1, 2, 3], [7, 8]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "public-display",
   "metadata": {},
   "outputs": [],
   "source": [
    "def create_pairs(X, Y):\n",
    "    if len(X) != len(Y):\n",
    "        #raise Exception('X and Y have different lengths')\n",
    "        raise ValueError('X and Y have different lengths')\n",
    "    \n",
    "    return list(zip(X, Y))\n",
    "\n",
    "print(create_pairs([1, 2, 3], [4, 5, 6]))\n",
    "print(create_pairs([1, 2, 3], [7, 8]))"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "documented-shakespeare",
   "metadata": {},
   "source": [
    "## Exercise\n",
    "\n",
    "Find all occurences of \"mathematic\" in file [cano.txt](https://sherlock-holm.es/ascii/)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "id": "appreciated-focus",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     aggregate he becomes a mathematical certainty. You can, for example,\n",
      "     mathematical faculty.  At the age of twenty-one he wrote a treatise\n",
      "     strength of it he won the Mathematical Chair at one of our smaller\n",
      "     to ex-Professor Moriarty of mathematical celebrity.\n",
      "     teeth I have barked my knuckles and the retiring mathematical coach,\n",
      "     mathematical master, was sure upon the point. Therefore, it is not\n",
      "     mathematics that it is said that there was no man in the scientific\n",
      "     the mathematical coach at the establishment, a tall, dark, thin man,\n",
      "     Murdoch, the mathematician. A moment later we confronted him upon the\n"
     ]
    }
   ],
   "source": [
    "file = open('cano.txt')\n",
    "line = file.readline()\n",
    "while line != '':    \n",
    "    if 'mathematic' in line.lower():\n",
    "        print(line, end='')  # lines in file end with '\\n'\n",
    "    line = file.readline()\n",
    "file.close()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "id": "clean-sleeve",
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     aggregate he becomes a mathematical certainty. You can, for example,\n",
      "     mathematical faculty.  At the age of twenty-one he wrote a treatise\n",
      "     strength of it he won the Mathematical Chair at one of our smaller\n",
      "     to ex-Professor Moriarty of mathematical celebrity.\n",
      "     teeth I have barked my knuckles and the retiring mathematical coach,\n",
      "     mathematical master, was sure upon the point. Therefore, it is not\n",
      "     mathematics that it is said that there was no man in the scientific\n",
      "     the mathematical coach at the establishment, a tall, dark, thin man,\n",
      "     Murdoch, the mathematician. A moment later we confronted him upon the\n"
     ]
    }
   ],
   "source": [
    "file = open('cano.txt')\n",
    "for line in file:\n",
    "    if 'mathematic' in line.lower():\n",
    "        print(line, end='')  # lines in file end with '\\n'\n",
    "file.close()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "id": "ordered-singer",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     aggregate he becomes a mathematical certainty. You can, for example,\n",
      "     mathematical faculty.  At the age of twenty-one he wrote a treatise\n",
      "     to ex-Professor Moriarty of mathematical celebrity.\n",
      "     teeth I have barked my knuckles and the retiring mathematical coach,\n",
      "     mathematical master, was sure upon the point. Therefore, it is not\n",
      "     mathematics that it is said that there was no man in the scientific\n",
      "     the mathematical coach at the establishment, a tall, dark, thin man,\n",
      "     Murdoch, the mathematician. A moment later we confronted him upon the\n"
     ]
    }
   ],
   "source": [
    "file = open('cano.txt')\n",
    "cano = file.readlines()  # read all data into list\n",
    "file.close()\n",
    "for line in cano:\n",
    "    if 'mathematic' in line:\n",
    "        print(line, end='')  # lines in file end with '\\n'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "id": "velvet-saskatchewan",
   "metadata": {
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     aggregate he becomes a mathematical certainty. You can, for example,\n",
      "     mathematical faculty.  At the age of twenty-one he wrote a treatise\n",
      "     to ex-Professor Moriarty of mathematical celebrity.\n",
      "     teeth I have barked my knuckles and the retiring mathematical coach,\n",
      "     mathematical master, was sure upon the point. Therefore, it is not\n",
      "     mathematics that it is said that there was no man in the scientific\n",
      "     the mathematical coach at the establishment, a tall, dark, thin man,\n",
      "     Murdoch, the mathematician. A moment later we confronted him upon the\n"
     ]
    }
   ],
   "source": [
    "with open('cano.txt') as file: # context manager that ensures files get closed\n",
    "    for line in file:\n",
    "        if 'mathematic' in line: print(line, end='')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 54,
   "id": "differential-madrid",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "could not open file\n"
     ]
    }
   ],
   "source": [
    "try:\n",
    "    with open('canon.txt') as file: # context manager that ensures files get closed\n",
    "        for line in file:\n",
    "            if 'mathematic' in line: print(line, end='')\n",
    "except FileNotFoundError:\n",
    "    print('could not open file')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "id": "curious-stretch",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "     aggregate he becomes a mathematical certainty. You can, for example,\n",
      "     mathematical faculty.  At the age of twenty-one he wrote a treatise\n",
      "     to ex-Professor Moriarty of mathematical celebrity.\n",
      "     teeth I have barked my knuckles and the retiring mathematical coach,\n",
      "     mathematical master, was sure upon the point. Therefore, it is not\n",
      "     mathematics that it is said that there was no man in the scientific\n",
      "     the mathematical coach at the establishment, a tall, dark, thin man,\n",
      "     Murdoch, the mathematician. A moment later we confronted him upon the\n"
     ]
    }
   ],
   "source": [
    "import os\n",
    "\n",
    "filename = 'cano.txt'\n",
    "if os.path.isfile(filename):\n",
    "    with open(filename) as file: # context manager that ensures files get closed\n",
    "        for line in file:\n",
    "            if 'mathematic' in line: print(line, end='')\n",
    "else:\n",
    "    print('could not open file')"
   ]
  }
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