Associate Array / Map / Dictionary + Hash Function Implements using Python

associate-array.ipynb

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   "source": [
    "from collections import Iterable\n",
    "from functools import reduce\n",
    "\n",
    "class HashTable(object):\n",
    "    def __init__(self, size=10):\n",
    "        self.size = 10\n",
    "        self.keys = [None] * self.size\n",
    "        self.values = [None] * self.size\n",
    "        \n",
    "    def __repr__(self):\n",
    "        return 'HashTable(size={})'.format(self.size)\n",
    "        \n",
    "    def put(self, key, value):  \n",
    "        index = self.hash(key)\n",
    "\n",
    "        while self.keys[index] is not None:  # collision\n",
    "            if self.keys[index] == key:  # update\n",
    "                self.values[index] = value  \n",
    "                return\n",
    "            index = (index + 1) % self.size  # rehash\n",
    "        \n",
    "        self.keys[index] = key\n",
    "        self.values[index] = value\n",
    "        \n",
    "    def get(self, key):\n",
    "        if key in self.keys:\n",
    "            return self.values[self.hash(key)]\n",
    "        return None\n",
    "    \n",
    "    def hash(self, key):        \n",
    "        if isinstance(key, Iterable):\n",
    "            sum = reduce(lambda prev, n: prev + ord(n), key, 0)\n",
    "        else:\n",
    "            sum = key\n",
    "            \n",
    "        return sum % self.size"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "h = HashTable()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "h.put('a', 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "h.get('a')"
   ]
  }
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