{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Python 简介"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## **Python** 历史"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Python` 的创始人为荷兰人吉多·范罗苏姆（`Guido van Rossum`）。1989年的圣诞节期间，吉多·范罗苏姆为了在阿姆斯特丹打发时间，决心开发一个新的脚本解释程序，作为 ABC 语言的一种继承。之所以选中 `Python` 作为程序的名字，是因为他是 BBC 电视剧——蒙提·派森的飞行马戏团（`Monty Python's Flying Circus`）的爱好者。\n",
    "\n",
    "1991年，第一个 Python 编译器诞生。它是用C语言实现的，并能够调用C语言的库文件。\n",
    "\n",
    "`Python 2.0` 于 2000 年 10 月 16 日发布，增加了实现完整的垃圾回收，并且支持 `Unic被移植到旧的 `Python 2.6/2.7` 版本。ode`。\n",
    "\n",
    "`Python 3.0` 于 2008 年 12 月 3 日发布，此版不完全兼容之前的 `Python` 源代码。不过，很多新特性后来也逐渐加入，更新版本已经不兼容2.0"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 安装python\n",
    "\n",
    "因为Python是跨平台的，它可以运行在Windows、Mac和各种Linux/Unix系统上。在Windows上写Python程序，放到Linux上也是能够运行的。\n",
    "\n",
    "安装后，你会得到Python解释器（就是负责运行Python程序的），一个命令行交互环境，还有一个简单的集成开发环境。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**目前，Python有两个版本，一个是2.x版，一个是3.x版，这两个版本是不兼容的。由于3.x版越来越普及，我们将以最新的Python 3版本为基础**"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**在Mac上安装Python**\n",
    "\n",
    "如果系统是OS X>=10.9，那么系统自带的Python版本是2.7。要安装最新的Python 3.7，有两个方法：\n",
    "方法一：从Python官网下载Python 3.7的安装程序（网速慢的同学请移步国内镜像），双击运行并安装；\n",
    "方法二：如果安装了Homebrew，直接通过命令brew install python3安装即可。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**在Linux上安装Python**\n",
    "\n",
    "如果你正在使用Linux，那我可以假定你有Linux系统管理经验，自行安装Python 3应该没有问题，建议大家使用linux进行开发。\n",
    "\n",
    "* 输入如下命令\n",
    "\n",
    "sudo add-apt-repository ppa:jonathonf/python-3.6\n",
    "\n",
    "sudo apt-get update\n",
    "\n",
    "sudo apt-get install python3.6\n",
    "\n",
    "* 更改默认值，python默认为Python2，现在修改为Python3\n",
    "\n",
    "sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 100\n",
    "\n",
    "sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 150"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**在Windows上安装Python**\n",
    "\n",
    "首先，根据你的Windows版本（64位还是32位）从Python的官方网站下载Python 3.7对应的64位安装程序或32位安装程序（网速慢的同学请移步国内镜像），然后，运行下载的EXE安装包。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Python解释器"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "当我们编写Python代码时，我们得到的是一个包含Python代码的以.py为扩展名的文本文件。要运行代码，就需要Python解释器去执行.py文件。\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**CPython**\n",
    "\n",
    "当我们从Python官方网站下载并安装好Python 3.x后，我们就直接获得了一个官方版本的解释器：CPython。这个解释器是用C语言开发的，所以叫CPython。在命令行下运行python就是启动CPython解释器。\n",
    "CPython是使用最广的Python解释器。教程的所有代码也都在CPython下执行。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**IPython**\n",
    "\n",
    "IPython是基于CPython之上的一个交互式解释器，也就是说，IPython只是在交互方式上有所增强，但是执行Python代码的功能和CPython是完全一样的。好比很多国产浏览器虽然外观不同，但内核其实都是调用了IE。\n",
    "CPython用>>>作为提示符，而IPython用In [序号]:作为提示符。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**PyPy**\n",
    "\n",
    "PyPy是另一个Python解释器，它的目标是执行速度。PyPy采用JIT技术，对Python代码进行动态编译（注意不是解释），所以可以显著提高Python代码的执行速度。\n",
    "绝大部分Python代码都可以在PyPy下运行，但是PyPy和CPython有一些是不同的，这就导致相同的Python代码在两种解释器下执行可能会有不同的结果。如果你的代码要放到PyPy下执行，就需要了解PyPy和CPython的不同点。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Jython**\n",
    "\n",
    "Jython是运行在Java平台上的Python解释器，可以直接把Python代码编译成Java字节码执行。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**IronPython**\n",
    "\n",
    "IronPython和Jython类似，只不过IronPython是运行在微软.Net平台上的Python解释器，可以直接把Python代码编译成.Net的字节码。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Python的解释器很多，但使用最广泛的还是CPython。如果要和Java或.Net平台交互，最好的办法不是用Jython或IronPython，而是通过网络调用来交互，确保各程序之间的独立性。**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 大家动起来，撸起袖子干"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "![撸起袖子干](为什么1.png)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 第一行Python代码\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "安装好 `Python` 之后，在命令行下输入：\n",
    "\n",
    "    python\n",
    "\n",
    "就可以进入 `Python` 解释器的页面。\n",
    "\n",
    "按照惯例，第一行代码应该是输出 `\"hello world!\"`："
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello world!\n"
     ]
    }
   ],
   "source": [
    "print(\"hello world!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "相对与 `Java，C` 等语言，`Python` 仅仅使用一行语句就完成的了这个任务。\n",
    "\n",
    "可以将这句话的内容保存到一个文本文件中，并使用后缀名 `.py` 结尾，例如 `hello_world.py`，在命令行下运行这个程序：\n",
    "\n",
    "    python hello_world.py\n",
    "\n",
    "也会输出 `\"hello world!\"` 的结果。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Python 之禅"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "在 Python 解释器下输入 \n",
    "\n",
    "import this\n",
    "\n",
    "会出来这样一首小诗："
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The Zen of Python, by Tim Peters\n",
      "\n",
      "Beautiful is better than ugly.\n",
      "Explicit is better than implicit.\n",
      "Simple is better than complex.\n",
      "Complex is better than complicated.\n",
      "Flat is better than nested.\n",
      "Sparse is better than dense.\n",
      "Readability counts.\n",
      "Special cases aren't special enough to break the rules.\n",
      "Although practicality beats purity.\n",
      "Errors should never pass silently.\n",
      "Unless explicitly silenced.\n",
      "In the face of ambiguity, refuse the temptation to guess.\n",
      "There should be one-- and preferably only one --obvious way to do it.\n",
      "Although that way may not be obvious at first unless you're Dutch.\n",
      "Now is better than never.\n",
      "Although never is often better than *right* now.\n",
      "If the implementation is hard to explain, it's a bad idea.\n",
      "If the implementation is easy to explain, it may be a good idea.\n",
      "Namespaces are one honking great idea -- let's do more of those!\n"
     ]
    }
   ],
   "source": [
    "import this"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "这首诗反映了Python的设计哲学——Python是一种追求优雅，明确，简单的编程语言，但事实上，产生这首诗的代码并没有写的那么简单易懂："
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The Zen of Python, by Tim Peters\n",
      "\n",
      "Beautiful is better than ugly.\n",
      "Explicit is better than implicit.\n",
      "Simple is better than complex.\n",
      "Complex is better than complicated.\n",
      "Flat is better than nested.\n",
      "Sparse is better than dense.\n",
      "Readability counts.\n",
      "Special cases aren't special enough to break the rules.\n",
      "Although practicality beats purity.\n",
      "Errors should never pass silently.\n",
      "Unless explicitly silenced.\n",
      "In the face of ambiguity, refuse the temptation to guess.\n",
      "There should be one-- and preferably only one --obvious way to do it.\n",
      "Although that way may not be obvious at first unless you're Dutch.\n",
      "Now is better than never.\n",
      "Although never is often better than *right* now.\n",
      "If the implementation is hard to explain, it's a bad idea.\n",
      "If the implementation is easy to explain, it may be a good idea.\n",
      "Namespaces are one honking great idea -- let's do more of those!\n"
     ]
    }
   ],
   "source": [
    "s = \"\"\"Gur Mra bs Clguba, ol Gvz Crgref\n",
    "\n",
    "Ornhgvshy vf orggre guna htyl.\n",
    "Rkcyvpvg vf orggre guna vzcyvpvg.\n",
    "Fvzcyr vf orggre guna pbzcyrk.\n",
    "Pbzcyrk vf orggre guna pbzcyvpngrq.\n",
    "Syng vf orggre guna arfgrq.\n",
    "Fcnefr vf orggre guna qrafr.\n",
    "Ernqnovyvgl pbhagf.\n",
    "Fcrpvny pnfrf nera'g fcrpvny rabhtu gb oernx gur ehyrf.\n",
    "Nygubhtu cenpgvpnyvgl orngf chevgl.\n",
    "Reebef fubhyq arire cnff fvyragyl.\n",
    "Hayrff rkcyvpvgyl fvyraprq.\n",
    "Va gur snpr bs nzovthvgl, ershfr gur grzcgngvba gb thrff.\n",
    "Gurer fubhyq or bar-- naq cersrenoyl bayl bar --boivbhf jnl gb qb vg.\n",
    "Nygubhtu gung jnl znl abg or boivbhf ng svefg hayrff lbh'er Qhgpu.\n",
    "Abj vf orggre guna arire.\n",
    "Nygubhtu arire vf bsgra orggre guna *evtug* abj.\n",
    "Vs gur vzcyrzragngvba vf uneq gb rkcynva, vg'f n onq vqrn.\n",
    "Vs gur vzcyrzragngvba vf rnfl gb rkcynva, vg znl or n tbbq vqrn.\n",
    "Anzrfcnprf ner bar ubaxvat terng vqrn -- yrg'f qb zber bs gubfr!\"\"\"\n",
    "\n",
    "d = {}\n",
    "for c in (65, 97):\n",
    "    for i in range(26):\n",
    "        d[chr(i+c)] = chr((i+13) % 26 + c)\n",
    "\n",
    "print (\"\".join([d.get(c, c) for c in s]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "a=-6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "# import keyword\t#导入keyword模块\n",
    "# keyword.kwlist"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "bool(a)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "ss = \"I'm OK!\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"I'm OK!\""
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "ss"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'I told my friend,\"Python is my favorite language!\"'"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "'I told my friend,\"Python is my favorite \\\n",
    "language!\"'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (<ipython-input-15-7e677ce58b8e>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-15-7e677ce58b8e>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    'I'm learning python.'\u001b[0m\n\u001b[1;37m       ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "'I'm learning python.'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "I'm learning\n",
      "Python.\n",
      "\\\n",
      "\\\n",
      "\\\\\\n\\\\\n"
     ]
    }
   ],
   "source": [
    "print('I\\'m learning\\nPython.')   #输出\n",
    "print('\\\\\\n\\\\')\n",
    "print(r'\\\\\\n\\\\')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "当计算机用"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "-1319896.0"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "4+6700/34*(2-6700)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# python文献地址\n",
    "https://docs.python.org/zh-cn/3/"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.8.0"
  },
  "toc": {
   "base_numbering": 1,
   "nav_menu": {},
   "number_sections": true,
   "sideBar": true,
   "skip_h1_title": false,
   "title_cell": "Table of Contents",
   "title_sidebar": "Contents",
   "toc_cell": false,
   "toc_position": {
    "height": "calc(100% - 180px)",
    "left": "10px",
    "top": "150px",
    "width": "306.875px"
   },
   "toc_section_display": true,
   "toc_window_display": true
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}