{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "a0d6f34d",
   "metadata": {},
   "source": [
    "A *set* is an un-ordered collection of *distinct* objects.   \n",
    "- Sets are like dictionaries except with only keys, no values.  \n",
    "- Like dictionaries, sets can only contain mutable (hashable objects).  \n",
    "- Checking if an item is in a set is fast, regardless of the size of the set."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "70ad56eb",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = {1, 2, 3, 4, 5}\n",
    "3 in s"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "940fb1f8",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{3, 4, 5, 6, 7}"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# uniqueness is inforced \n",
    "t = {3, 4, 5, 6, 6, 6, 7}\n",
    "t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "e7c3d646",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{3, 4, 5}"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# intersection\n",
    "s & t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "ed39ffe3",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{1, 2, 3, 4, 5, 6, 7}"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# union\n",
    "s | t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "6bec4721",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{1, 2, 3, 4, 5}\n",
      "{3, 4, 5, 6, 7}\n",
      "{1, 2}\n",
      "{6, 7}\n"
     ]
    }
   ],
   "source": [
    "# set difference\n",
    "print(s)\n",
    "print(t)\n",
    "print(s - t)\n",
    "print(t - s)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "670b668a",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{1, 2, 6, 7}"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# set symmetric difference \n",
    "s ^ t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "db3de92e",
   "metadata": {},
   "outputs": [],
   "source": [
    "# compare the speed of finding an item in a list\n",
    "big_list = list(range(10**8))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "b354b127",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "-1 in big_list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "id": "c64263bd",
   "metadata": {},
   "outputs": [],
   "source": [
    "big_set = set(big_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "ea46ab8b",
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "-1 in big_set"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "43ae95ce",
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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