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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#  7.3 成员关系"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "集合支持存在性测试，可用 x in s 和 x not in s操作判断数据x是否包含在集合s中，是否是该集合的成员。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "在使用in 时它是先将所要查的数通过hash函数转换为一个巨大的整数，然后直接一步到位，所以它的<font color='red'>效率非常高</font>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "####  `x in s` ：如果 x 是集合 s 的成员则返回值值为True，否则为False。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "####  `x not in s` ：如果 x 不是集合 s 的成员则返回值为True，否则为False。即返回x in s 取反后的值。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'o', 'n', 'a', 'r', 'g', 'm', 'i', 'P'}\n",
      "False\n",
      "True\n",
      "True\n"
     ]
    }
   ],
   "source": [
    "s = set('Programming')        \n",
    "print(s)                      # s = {'P', 'a', 'i', 'n', 'm', 'r', 'o', 'g'}\n",
    "print('k' in s)               # s 中不存在元素'k'，返回False\n",
    "print('P' in s)               # s 中存在元素'P'，返回True\n",
    "print('c' not in s)           # s 中不存在元素'c'，返回True"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 实例1 查询输入的品牌是否是2019年畅销手机品牌。\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdin",
     "output_type": "stream",
     "text": [
      " 华为\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "华为是2019年畅销手机品牌\n"
     ]
    }
   ],
   "source": [
    "# 下面的二维列表中包含2019年畅销手机品牌及其市场份额\n",
    "sale2019 =  [['华为', '34.3'], ['vivo', '18.5'], ['OPPO', '18.6'], \n",
    "             ['小米', '12.3'], ['Apple', '8.6'], ['魅族', '1.8'], \n",
    "             ['三星', '1.5'], ['联想', '0.8'], ['中兴', '0.6']]\n",
    "\n",
    "saleSet2019 = {x[0] for x in sale2019}   # 通过集合推导式得到2019年畅销手机品牌集合\n",
    "\n",
    "brand = input()            # 输入要查询的品牌\n",
    "if brand in saleSet2019:   # 判断要查询的品牌是否在集合中\n",
    "    print(f'{brand}是2019年畅销手机品牌')\n",
    "else:\n",
    "    print(f'{brand}不是2019年畅销手机品牌')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 实例2 省份查询"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "citys = {'北京', '上海', '天津', '重庆'}\n",
    "autonomous_region = {'内蒙古', '广西', '西藏', '宁夏', '新疆'}\n",
    "special_administrative_region = {'香港', '澳门'}\n",
    "province = input()\n",
    "if province in citys:\n",
    "    print(f'{province}是直辖市')\n",
    "elif province in autonomous_region:\n",
    "    print(f'{province}是自治区')\n",
    "elif province in special_administrative_region:\n",
    "    print(f'{province}是特别行政区')\n",
    "else:\n",
    "    print(f'{province}是一般省份')\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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