210310Day8.ipynb

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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## if语句"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Audi\n",
      "BMW\n",
      "Subaru\n",
      "Toyota\n"
     ]
    }
   ],
   "source": [
    "cars=[\"audi\",\"bmw\",\"subaru\",\"toyota\"]\n",
    "for car in cars:\n",
    "    if car!=\"bmw\":\n",
    "        print(car.title())\n",
    "    else:\n",
    "        print(car.upper())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### \"==\"相等运算符，如果两边值相等返回True，否则返回False\n",
    "两个大小写不同的但是内容相同的会被视为不相等"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### \"!=\"检查不相等，如果两边值不相等返回True，否则返回False"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### \">\"、\">=\"、\"<\"、\"<=\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "car=\"bmw\"\n",
    "car==\"BMW\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "所以只想检查变量的值，可以把变量的值全转换为小写"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "car=\"Bmw\"\n",
    "car.lower()==\"bmw\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "你成年了\n"
     ]
    }
   ],
   "source": [
    "age=19\n",
    "if age>=18:\n",
    "    print(\"你成年了\")\n",
    "else:\n",
    "    print(\"你没成年\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### and 和 or 可以同时检查两个变量"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "两人没成年\n"
     ]
    }
   ],
   "source": [
    "age_1=15\n",
    "age_2=16\n",
    "if (age_1>=18) or (age_2>=18):\n",
    "    print(\"两人至少有一个人成年了\")\n",
    "else:\n",
    "    print(\"两人没成年\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\n",
    "age_1==True"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### in 是关键字，用于判断前面的值是否包含于列表中"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 36,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dishes=(\"可乐\",\"炸鸡\",\"汉堡\",\"薯条\",\"炸鱼\")\n",
    "\"可乐\"in dishes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### not in 是关键字，用于判断前面的值是否不包含于列表中"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"麻辣小蟑螂\"not in dishes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### 布尔表达式"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n",
      "2\n",
      "5\n",
      "26\n",
      "677\n",
      "458330\n",
      "210066388901\n",
      "44127887745906175987802\n",
      "1947270476915296449559703445493848930452791205\n",
      "3791862310265926082868235028027893277370233152247388584761734150717768254410341175325352026\n",
      "14378219780015246281818710879551167697596193767663736497089725524386087657390556152293078723153293423353330879856663164406809615688082297859526620035327291442156498380795040822304677\n"
     ]
    }
   ],
   "source": [
    "a=0\n",
    "for i in range(0,11):\n",
    "    a=a*a+1\n",
    "    print(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2.65"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(7*3+5.5)/10"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "王一博帅\n"
     ]
    }
   ],
   "source": [
    "words=\"王一博\"\n",
    "if words==\"王一博\":\n",
    "    print(f\"{words}帅\")\n",
    "else:\n",
    "    print((f\"{words}丑\"))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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