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   "source": [
    "# Devoir sur les iterateurs et les générateurs \n",
    "## Solutions\n",
    "\n",
    "### 1er problème\n",
    "\n",
    "Créer un générateur qui génère les carrés de nombres jusqu'à un certain nombre N."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def gensquares(N):\n",
    "    for i in range(N):\n",
    "        yield i ** 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0\n",
      "1\n",
      "4\n",
      "9\n",
      "16\n",
      "25\n",
      "36\n",
      "49\n",
      "64\n",
      "81\n"
     ]
    }
   ],
   "source": [
    "for x in gensquares(10):\n",
    "    print (x)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 2ième problème\n",
    "\n",
    "Créez un générateur qui donne «n» nombres aléatoires entre un nombre de départ et un nombre d'arrivée (qui sont les pramètres d'entrée).\n",
    "Remarque: utilisez la bibliothèque random.\n",
    "\n",
    "Par exemple:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "import random\n",
    "\n",
    "random.randint(1,10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def rand_num(départ,arrivée,n):\n",
    "    \n",
    "    for i in range(n):\n",
    "        yield random.randint(départ, arrivée)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "8\n",
      "5\n",
      "1\n",
      "3\n",
      "7\n",
      "1\n",
      "3\n",
      "9\n",
      "2\n",
      "9\n",
      "3\n",
      "1\n"
     ]
    }
   ],
   "source": [
    "for num in rand_num(1,10,12):\n",
    "    print (num)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 3ième problème\n",
    "\n",
    "Utilisez la fonction iter () pour convertir la chaîne ci-dessous"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "b\n"
     ]
    }
   ],
   "source": [
    "s = 'bonjour'\n",
    "\n",
    "s = iter(s)\n",
    "\n",
    "print (next(s))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 4ième problème\n",
    "\n",
    "Expliquez un cas d'utilisation pour un générateur en utilisant une déclaration yield plutôt que d'utiliser une fonction normale avec une instruction de retour.\n",
    "\n",
    "**If the output has the potential of taking up a large amount of memory and you only intend to iterate through it, you would want to use a generator. (Multiple answers are acceptable here!)**"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Crédits supplémentaires !\n",
    "Pouvez-vous expliquer ce que *gencomp* est dans le code ci-dessous?\n",
    "(Note: Nous n'avons jamais couvert cela en cours ! Vous devrez faire quelques appels à Google  et Stack Overflow !)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "4\n",
      "5\n"
     ]
    }
   ],
   "source": [
    "ma_liste = [1,2,3,4,5]\n",
    "\n",
    "gencomp = (item for item in ma_liste if item > 3)\n",
    "\n",
    "for item in gencomp:\n",
    "    print (item)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Conseil google: generator comprehension !\n",
    "\n",
    "# Beau boulot !"
   ]
  }
 ],
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