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  {
   "cell_type": "markdown",
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   "source": [
    "# Encapsulación\n",
    "Consiste en denegar el acceso a los atributos y métodos internos de la clase desde el exterior.\n",
    "\n",
    "En Python no existe, pero se puede simular precediendo atributos y métodos con dos barras bajas __:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "class Ejemplo:\n",
    "    __atributo_privado = \"Soy un atributo inalcanzable desde fuera\"\n",
    "    \n",
    "    def __metodo_privado(self):\n",
    "        print(\"Soy un método inalcanzable desde fuera\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "e = Ejemplo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "AttributeError",
     "evalue": "'Ejemplo' object has no attribute '__atributo_privado'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-3-73328dd71c23>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0me\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m__atributo_privado\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m: 'Ejemplo' object has no attribute '__atributo_privado'"
     ]
    }
   ],
   "source": [
    "e.__atributo_privado"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "AttributeError",
     "evalue": "'Ejemplo' object has no attribute '__metodo_privado'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-4-164c67db4a9b>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0me\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0m__metodo_privado\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mAttributeError\u001b[0m: 'Ejemplo' object has no attribute '__metodo_privado'"
     ]
    }
   ],
   "source": [
    "e.__metodo_privado()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Cómo acceder\n",
    "Internamente la clase sí puede acceder a sus atributos y métodos encapsulados, el truco consiste en crear sus equivalentes \"publicos\":"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "class Ejemplo:\n",
    "    __atributo_privado = \"Soy un atributo inalcanzable desde fuera\"\n",
    "    \n",
    "    def __metodo_privado(self):\n",
    "        print(\"Soy un método inalcanzable desde fuera\")\n",
    "        \n",
    "    def atributo_publico(self):\n",
    "        return self.__atributo_privado\n",
    "        \n",
    "    def metodo_publico(self):\n",
    "        return self.__metodo_privado()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "e = Ejemplo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'Soy un atributo inalcanzable desde fuera'"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "e.atributo_publico()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Soy un método inalcanzable desde fuera\n"
     ]
    }
   ],
   "source": [
    "e.metodo_publico()"
   ]
  }
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