lektion3.ipynb

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   "source": [
    " # Eine Einführung in die objektorientierte Programmierung\n",
    " Eine ausführliche Beschreibung finden Sie hier:\n",
    " https://www.python-kurs.eu/klassen.php\n",
    "\n",
    " Wir haben bereits vordefinierte Objekte und Methoden von Klassen benutzt.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true,
    "slideshow": {
     "slide_type": "slide"
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   },
   "outputs": [],
   "source": [
    "liste1 = [1,2,3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1, 2, 3]"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "liste1  # liste1. + TAB Taste"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
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     "slide_type": "fragment"
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    {
     "data": {
      "text/plain": [
       "['__abs__',\n",
       " '__add__',\n",
       " '__and__',\n",
       " '__bool__',\n",
       " '__ceil__',\n",
       " '__class__',\n",
       " '__delattr__',\n",
       " '__dir__',\n",
       " '__divmod__',\n",
       " '__doc__',\n",
       " '__eq__',\n",
       " '__float__',\n",
       " '__floor__',\n",
       " '__floordiv__',\n",
       " '__format__',\n",
       " '__ge__',\n",
       " '__getattribute__',\n",
       " '__getnewargs__',\n",
       " '__gt__',\n",
       " '__hash__',\n",
       " '__index__',\n",
       " '__init__',\n",
       " '__init_subclass__',\n",
       " '__int__',\n",
       " '__invert__',\n",
       " '__le__',\n",
       " '__lshift__',\n",
       " '__lt__',\n",
       " '__mod__',\n",
       " '__mul__',\n",
       " '__ne__',\n",
       " '__neg__',\n",
       " '__new__',\n",
       " '__or__',\n",
       " '__pos__',\n",
       " '__pow__',\n",
       " '__radd__',\n",
       " '__rand__',\n",
       " '__rdivmod__',\n",
       " '__reduce__',\n",
       " '__reduce_ex__',\n",
       " '__repr__',\n",
       " '__rfloordiv__',\n",
       " '__rlshift__',\n",
       " '__rmod__',\n",
       " '__rmul__',\n",
       " '__ror__',\n",
       " '__round__',\n",
       " '__rpow__',\n",
       " '__rrshift__',\n",
       " '__rshift__',\n",
       " '__rsub__',\n",
       " '__rtruediv__',\n",
       " '__rxor__',\n",
       " '__setattr__',\n",
       " '__sizeof__',\n",
       " '__str__',\n",
       " '__sub__',\n",
       " '__subclasshook__',\n",
       " '__truediv__',\n",
       " '__trunc__',\n",
       " '__xor__',\n",
       " 'bit_length',\n",
       " 'conjugate',\n",
       " 'denominator',\n",
       " 'from_bytes',\n",
       " 'imag',\n",
       " 'numerator',\n",
       " 'real',\n",
       " 'to_bytes']"
      ]
     },
     "execution_count": 3,
     "metadata": {},
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    }
   ],
   "source": [
    "a = -23\n",
    "type(a)\n",
    "dir(a)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
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   },
   "source": [
    "## Eine erste Klasse, die nichts kann.\n",
    "Die minimale Definition einer Klasse in Python hat die Form"
   ]
  },
  {
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   "execution_count": 4,
   "metadata": {
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   "source": [
    "class ErsteKlasse(object):\n",
    "    pass # pass gibt an, dass hier noch irgendwas hin soll\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
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    {
     "data": {
      "text/plain": [
       "<__main__.ErsteKlasse at 0x7fad38245d68>"
      ]
     },
     "execution_count": 5,
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   ],
   "source": [
    "p = ErsteKlasse()\n",
    "p"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
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     "data": {
      "text/plain": [
       "['__class__',\n",
       " '__delattr__',\n",
       " '__dict__',\n",
       " '__dir__',\n",
       " '__doc__',\n",
       " '__eq__',\n",
       " '__format__',\n",
       " '__ge__',\n",
       " '__getattribute__',\n",
       " '__gt__',\n",
       " '__hash__',\n",
       " '__init__',\n",
       " '__init_subclass__',\n",
       " '__le__',\n",
       " '__lt__',\n",
       " '__module__',\n",
       " '__ne__',\n",
       " '__new__',\n",
       " '__reduce__',\n",
       " '__reduce_ex__',\n",
       " '__repr__',\n",
       " '__setattr__',\n",
       " '__sizeof__',\n",
       " '__str__',\n",
       " '__subclasshook__',\n",
       " '__weakref__',\n",
       " 'f',\n",
       " 'n']"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "class ZweiteKlasse(object):\n",
    "    \"\"\" eine zweite Klasse \"\"\"\n",
    "    n = 1234\n",
    "    def f(x):\n",
    "        return x**2\n",
    "\n",
    "z = ZweiteKlasse\n",
    "z\n",
    "dir(z)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Klasse Student"
   ]
  },
  {
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   "execution_count": 7,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hallo Li Ping\n",
      "Hallo mein Name ist Li Ping\n",
      "Hallo mein Name ist Lisa Paul\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[1, 4]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
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   ],
   "source": [
    "class Student(object):\n",
    "    \n",
    "    noten = []                      # \n",
    "    \n",
    "    def __init__(self,Vn,Nn,MatNr):\n",
    "        self.Vorname = Vn\n",
    "        self.Nachname = Nn\n",
    "        self.MatrikelNummer = MatNr\n",
    "    #'__init__ wird automatisch beim Erstellen eines Objektes aufgerufen\n",
    "\n",
    "    # Klassenmethoden\n",
    "    def notehinzufuegen(self,note):\n",
    "        self.noten.append(note)\n",
    "        \n",
    "    def hallo(self):\n",
    "        print('Hallo mein Name ist {0} {1}'.format(self.Vorname,self.Nachname))\n",
    " \n",
    "           \n",
    "a = Student('Li','Ping',101)\n",
    "b = Student('Lisa','Paul',102)\n",
    "a.notehinzufuegen(1)\n",
    "b.notehinzufuegen(4)\n",
    "\n",
    "print('Hallo {0} {1}'.format(a.Vorname,a.Nachname))\n",
    "a.hallo()\n",
    "b.hallo()\n",
    "\n",
    "a.noten"
   ]
  },
  {
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   "source": [
    "# Bessere Lösung\n"
   ]
  },
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   "source": [
    "class Student(object):\n",
    "     \n",
    "    def __init__(self,Vn,Nn,MatNr):\n",
    "        self.Vorname = Vn\n",
    "        self.Nachname = Nn\n",
    "        self.MatrikelNummer = MatNr\n",
    "        self.noten = []\n",
    "        \n",
    "    def notehinzufuegen(self,note):\n",
    "        self.noten.append(note)\n",
    "        \n",
    "    def hallo(self):\n",
    "        print('Hallo mein Name ist {0} {1}'.format(self.Vorname,self.Nachname))\n",
    " "
   ]
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   "cell_type": "code",
   "execution_count": 9,
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   "outputs": [
    {
     "data": {
      "text/plain": [
       "([1], [4])"
      ]
     },
     "execution_count": 9,
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   ],
   "source": [
    "a = Student('Li','Ping',101)\n",
    "b = Student('Lisa','Paul',102)\n",
    "a.notehinzufuegen(1)\n",
    "b.notehinzufuegen(4)\n",
    "\n",
    "a.noten, b.noten"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
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     "slide_type": "slide"
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   "source": [
    " # Rules regarding self\n",
    " (from Lantangen's book, page 419):\n",
    "\n",
    " 1) Any class method must have self as first argument. (The name can be any \n",
    "    valid variable name, but the name self is a widely established convention in\n",
    "     Python.) \n",
    "\n",
    " 2) self represents an (arbitrary) instance of the class.\n",
    "\n",
    " 3) To access any class attribute inside class methods, we must prefix with self,\n",
    " as in self.name, where name is the name of the attribute.\n",
    "\n",
    " 4) self is dropped as argument in calls to class methods.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
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     "slide_type": "slide"
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hallo mein Name ist Li Ping\n",
      "HALLO Li Deine email ist Li.Ping@hhu.de\n"
     ]
    }
   ],
   "source": [
    "class Student(object):\n",
    "    \n",
    "    def __init__(self,Vn,Nn,MatNr):\n",
    "        self.Vorname = Vn\n",
    "        self.Nachname = Nn\n",
    "        self.MatrikelNummer = MatNr\n",
    "        self.noten = []\n",
    "        \n",
    "    def saghallo(self):\n",
    "        print('Hallo mein Name ist {0} {1}'.format(self.Vorname,self.Nachname))\n",
    " \n",
    "    def brief(self):\n",
    "        return 'HALLO {0} Deine email ist {1}'.format(self.Vorname,self.email())\n",
    "        \n",
    "    def email(self):\n",
    "        return '{0}.{1}@hhu.de'.format(self.Vorname,self.Nachname)\n",
    "            \n",
    "a = Student('Li','Ping',101)\n",
    "b = Student('Lisa','Paul',102)\n",
    "a.saghallo()\n",
    "print(a.brief())\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
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     "slide_type": "slide"
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   "source": [
    "## Ein mathematisches Beispiel\n",
    "Eine Klasse für Polynome \n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
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   "outputs": [],
   "source": [
    "class Polynom(object):\n",
    "    \"\"\" Polynomklasse Beschreibung .....\n",
    "    \"\"\"\n",
    "    def __init__(self,dp):\n",
    "        if isinstance(dp,(int,float,complex)):\n",
    "            dp = {0:dp}\n",
    "        self.dp = dp\n",
    "        self.degree = max(dp.keys())\n",
    "        \n",
    "    def __repr__(self):\n",
    "        polystr = ''\n",
    "        for k in sorted(self.dp):\n",
    "            polystr = polystr + '{0:+g}*X^{1}'.format(self.dp[k],k)\n",
    "        return 'Polynom: ' + polystr \n",
    "    \n",
    "    def __add__(self,other):\n",
    "        spow = set(self.dp.keys())\n",
    "        opow = set(other.dp.keys())\n",
    "        pows = spow.union(opow)\n",
    "        pps = dict()\n",
    "        for k in pows:\n",
    "            if k in spow:\n",
    "                if k in opow:\n",
    "                    pps[k] = self.dp[k] + other.dp[k]\n",
    "                else:\n",
    "                    pps[k] = self.dp[k]\n",
    "            else:\n",
    "                pps[k] =  other.dp[k]\n",
    "        \n",
    "        return Polynom(pps)\n",
    "    \n",
    "    def __sub__(self,other):\n",
    "        \"\"\" Substraktion zweier Polynomen \n",
    "        \"\"\"\n",
    "        selfpow = set(self.dp.keys())\n",
    "        otherpow = set(other.dp.keys())\n",
    "        pows = selfpow.union(otherpow)\n",
    "        erg = dict()\n",
    "        for k in pows:\n",
    "            if k in selfpow:\n",
    "                if k in otherpow:\n",
    "                    erg[k] = self.dp[k] - other.dp[k]\n",
    "                else:\n",
    "                    erg[k] = self.dp[k]\n",
    "            else:\n",
    "                erg[k] =  -other.dp[k]\n",
    "        \n",
    "        return Polynom(erg)\n",
    "    def __call__(self,x):\n",
    "        \"\"\" Auswertung des Polynoms \n",
    "        \"\"\"\n",
    "        return sum([self.dp[k]*x**k for k in self.dp])\n",
    "    \n",
    "    def __mul__(self,other):\n",
    "        \"\"\" Multiplikation eines Polynoms mit einem Skalar \n",
    "        TODO Polynommultiplikation\n",
    "        \"\"\"\n",
    "        erg = dict()\n",
    "        if isinstance(other,(int,float,complex)):\n",
    "            for k in self.dp:\n",
    "                erg[k] = self.dp[k] *other       \n",
    "            return Polynom(erg)\n",
    "        \n",
    "    __rmul__ = __mul__\n",
    "            "
   ]
  },
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   "execution_count": 12,
   "metadata": {
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   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(Polynom: +1*X^0+2.5*X^10, Polynom: +0.666667*X^0+34*X^5)"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "pd = {0:1,10:2.5}\n",
    "qd = {0:2/3,5:34}\n",
    "p = Polynom(pd)\n",
    "q = Polynom(qd)\n",
    "p, q"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
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     "slide_type": "fragment"
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   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Polynom: +1*X^0+2.5*X^10\n"
     ]
    }
   ],
   "source": [
    "print(p)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Polynom: +1.66667*X^0+34*X^5+2.5*X^10"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "p+q"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Polynom: +0.333333*X^0-34*X^5+2.5*X^10"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "p-q"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Polynom: +2*X^0+5*X^10"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "2*p"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Polynom: +2*X^0+5*X^10"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "p*2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Polynom: +2.66667*X^0+34*X^5+5*X^10"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "2*p+q"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2561.0"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "p(2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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