Ch3 Str and Set.ipynb

{
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   "cell_type": "code",
   "execution_count": 1,
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    {
     "data": {
      "text/plain": "[]"
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "from collections import defaultdict\n",
    "\n",
    "index = defaultdict(list)\n",
    "index[1]\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "outputs": [],
   "source": [
    "index.get(2)"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "outputs": [],
   "source": [
    "class StrKeyDict0(dict):\n",
    "\n",
    "    def __missing__(self, key):\n",
    "        if isinstance(key, str):\n",
    "            raise KeyError(key)\n",
    "        else:\n",
    "            return self[str(key)]\n",
    "\n",
    "    def get(self, key, default=None):\n",
    "        try:\n",
    "            return self[key]\n",
    "        except KeyError:\n",
    "            return default\n",
    "\n",
    "    def __contains__(self, key):\n",
    "        return key in self.keys() or str(key) in self.keys()"
   ],
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  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "outputs": [],
   "source": [
    "d = StrKeyDict0([('2', 'two'), ('4', 'four')])"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "outputs": [
    {
     "data": {
      "text/plain": "'two'"
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d[2]"
   ],
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     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "outputs": [],
   "source": [
    "import collections\n",
    "\n",
    "\n",
    "class StrKeyDict(collections.UserDict):\n",
    "\n",
    "    def __missing__(self, key):\n",
    "        if isinstance(key, str):\n",
    "            raise KeyError(key)\n",
    "        return self[str(key)]\n",
    "\n",
    "    def __contains__(self, key):\n",
    "        return str(key) in self.data\n",
    "\n",
    "    def __setitem__(self, key, item):\n",
    "        self.data[str(key)] = item"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "'mappingproxy' object does not support item assignment",
     "output_type": "error",
     "traceback": [
      "\u001B[1;31m---------------------------------------------------------------------------\u001B[0m",
      "\u001B[1;31mTypeError\u001B[0m                                 Traceback (most recent call last)",
      "\u001B[1;32m<ipython-input-11-49d0a474f193>\u001B[0m in \u001B[0;36m<module>\u001B[1;34m\u001B[0m\n\u001B[0;32m      3\u001B[0m \u001B[0md\u001B[0m \u001B[1;33m=\u001B[0m \u001B[1;33m{\u001B[0m\u001B[1;36m1\u001B[0m\u001B[1;33m:\u001B[0m \u001B[1;36m1\u001B[0m\u001B[1;33m}\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[0;32m      4\u001B[0m \u001B[0md_proxy\u001B[0m \u001B[1;33m=\u001B[0m \u001B[0mMappingProxyType\u001B[0m\u001B[1;33m(\u001B[0m\u001B[0md\u001B[0m\u001B[1;33m)\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[1;32m----> 5\u001B[1;33m \u001B[0md_proxy\u001B[0m\u001B[1;33m[\u001B[0m\u001B[1;36m2\u001B[0m\u001B[1;33m]\u001B[0m\u001B[1;33m=\u001B[0m\u001B[1;36m2\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[0m\u001B[0;32m      6\u001B[0m \u001B[0md_proxy\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n",
      "\u001B[1;31mTypeError\u001B[0m: 'mappingproxy' object does not support item assignment"
     ]
    }
   ],
   "source": [
    "from types import MappingProxyType\n",
    "\n",
    "d = {1: 1}\n",
    "d_proxy = MappingProxyType(d)\n",
    "d_proxy[2]=2\n",
    "d_proxy"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "outputs": [
    {
     "data": {
      "text/plain": "True"
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "hash(1)==hash(1.0)"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n",
      "230584300921345\n"
     ]
    }
   ],
   "source": [
    "print(hash(1))\n",
    "print(hash(1.0001))"
   ],
   "metadata": {
    "collapsed": false,
    "pycharm": {
     "name": "#%%\n"
    }
   }
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "outputs": [
    {
     "ename": "RuntimeError",
     "evalue": "dictionary keys changed during iteration",
     "output_type": "error",
     "traceback": [
      "\u001B[1;31m---------------------------------------------------------------------------\u001B[0m",
      "\u001B[1;31mRuntimeError\u001B[0m                              Traceback (most recent call last)",
      "\u001B[1;32m<ipython-input-3-182f7ffbe795>\u001B[0m in \u001B[0;36m<module>\u001B[1;34m\u001B[0m\n\u001B[0;32m      1\u001B[0m \u001B[0md\u001B[0m \u001B[1;33m=\u001B[0m \u001B[1;33m{\u001B[0m\u001B[1;36m1\u001B[0m\u001B[1;33m:\u001B[0m \u001B[1;36m1\u001B[0m\u001B[1;33m}\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[1;32m----> 2\u001B[1;33m \u001B[1;32mfor\u001B[0m \u001B[0mk\u001B[0m \u001B[1;32min\u001B[0m \u001B[0md\u001B[0m\u001B[1;33m.\u001B[0m\u001B[0mkeys\u001B[0m\u001B[1;33m(\u001B[0m\u001B[1;33m)\u001B[0m\u001B[1;33m:\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[0m\u001B[0;32m      3\u001B[0m     \u001B[0md\u001B[0m\u001B[1;33m[\u001B[0m\u001B[1;34m'i{}'\u001B[0m\u001B[1;33m.\u001B[0m\u001B[0mformat\u001B[0m\u001B[1;33m(\u001B[0m\u001B[0mk\u001B[0m\u001B[1;33m)\u001B[0m\u001B[1;33m]\u001B[0m \u001B[1;33m=\u001B[0m \u001B[0md\u001B[0m\u001B[1;33m.\u001B[0m\u001B[0mpop\u001B[0m\u001B[1;33m(\u001B[0m\u001B[0mk\u001B[0m\u001B[1;33m)\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n\u001B[0;32m      4\u001B[0m \u001B[0mprint\u001B[0m\u001B[1;33m(\u001B[0m\u001B[0md\u001B[0m\u001B[1;33m)\u001B[0m\u001B[1;33m\u001B[0m\u001B[1;33m\u001B[0m\u001B[0m\n",
      "\u001B[1;31mRuntimeError\u001B[0m: dictionary keys changed during iteration"
     ]
    }
   ],
   "source": [
    "d = {1: 1}\n",
    "for k in d.keys():\n",
    "    d['i{}'.format(k)] = d.pop(k)\n",
    "print(d)"
   ],
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