05-Object Oriented Programming/.ipynb_checkpoints/Special Functions-checkpoint.ipynb

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   "source": [
    "class Book():\n",
    "    def __init__(self,title,author,pages):\n",
    "        self.title = title\n",
    "        self.author = author\n",
    "        self.pages = pages\n",
    "    def __str__(self):\n",
    "        return f'{self.title} by {self.author}'\n",
    "    def __len__(self):\n",
    "        return self.pages\n",
    "    def __del__(self):\n",
    "        print('A book has been deleted')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {},
   "outputs": [],
   "source": [
    "b = Book('Selfish Gene','Richard Dawkins',500)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Selfish Gene by Richard Dawkins\n"
     ]
    }
   ],
   "source": [
    "print(b)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "500"
      ]
     },
     "execution_count": 47,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "len(b)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 48,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "A book has been deleted\n"
     ]
    }
   ],
   "source": [
    "del b"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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