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<!DOCTYPE html>
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<title>python自动化测试人工智能</title>
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<h1><a href="/python3_crash_ch11.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程11命令行自动化工具与pexpect">[雪峰磁针石博客]python3快速入门教程11命令行自动化工具与pexpect</a></h1>
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<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T13:50:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="pexpect">命令行自动化与pexpect</h2>
<h3 id="_1">简介</h3>
<p>Pexpect 是一个用来启动交互式命令行子程序并对其进行自动控制的 Python 工具模块。 Pexpect 可以用来和像 ssh、ftp、passwd、telnet 等命令行程序进行自动交互。可广泛用于自动化运维和测试，实现同时控制多台设备和自动化。Linux中的知名装包软件就使用了Pexpect。 Pexpect在IBM，alibaba，google等公司有广泛使用，在https://pypi.python.org/pypi/pexpect 的日下载量一万左右。</p>
<p>纯python实现，依赖pty模块(不支持Windows)。</p>
<p>最新英文版文档参见：<a href="http://pexpect.readthedocs.org/en/latest/">http://pexpect.readthedocs.org/en/latest/</a></p>
<p>安装：</p>
<p>版本要求：Python 2.6、3.2 或以上</p>
<h3 id="_2">快速入门</h3>
<p>ssh登录是常用的操作，过程如下：</p>
<div class="highlight"><pre><span></span><span class="c1"># ssh test@172 …</span></pre></div>
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<h1><a href="/python3_crash_ch9_1.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程9重要的标准库-基础篇">[雪峰磁针石博客]python3快速入门教程9重要的标准库-基础篇</a></h1>
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<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T13:50:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h3 id="_1">操作系统接口</h3>
<p>os模块提供了一些与操作系统交互的函数:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="kn">import</span> <span class="nn">os</span>
<span class="o">>>></span> <span class="n">os</span><span class="o">.</span><span class="n">getcwd</span><span class="p">()</span> <span class="c1"># Return the current working directory</span>
<span class="s1">'C:</span><span class="se">\\</span><span class="s1">Python36'</span>
<span class="o">>>></span> <span class="n">os</span><span class="o">.</span><span class="n">chdir</span><span class="p">(</span><span class="s1">'/server/accesslogs'</span><span class="p">)</span> <span class="c1"># Change current working directory</span>
<span class="o">>>></span> <span class="n">os</span><span class="o">.</span><span class="n">system</span><span class="p">(</span><span class="s1">'mkdir today'</span><span class="p">)</span> <span class="c1"># Run the command mkdir in the system shell</span>
<span class="mi">0</span>
</pre></div>
<p>用import os而不是from os import *。否则os.open()会覆盖内置函数open()。</p>
<p>对os这样的大型模块, 内置的open()和help()函数非常有用:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="kn">import</span> <span class="nn">os</span>
<span class="o">>>></span> <span class="nb">dir</span><span class="p">(</span><span class="n">os</span><span class="p">)</span>
<span class="o"><</span><span class="n">returns …</span></pre></div>
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<h1><a href="/python3_crash_ch8.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程8错误和异常">[雪峰磁针石博客]python3快速入门教程8错误和异常</a></h1>
</header>
<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T13:40:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <p>Python 中(至少)有两种错误：语法错误(syntax errors)和异常(exceptions)。</p>
<h2 id="_1">语法错误</h2>
<p>语法错误又称作解析错误:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="k">while</span> <span class="bp">True</span> <span class="k">print</span><span class="p">(</span><span class="s1">'Hello world'</span><span class="p">)</span>
<span class="n">File</span> <span class="s2">"<stdin>"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">1</span>
<span class="k">while</span> <span class="bp">True</span> <span class="k">print</span><span class="p">(</span><span class="s1">'Hello world'</span><span class="p">)</span>
<span class="o">^</span>
<span class="ne">SyntaxError</span><span class="p">:</span> <span class="n">invalid</span> <span class="n">syntax</span>
</pre></div>
<p>语法分析器指出错误行，并且在检测到错误的位置前面显示^。 </p>
<h2 id="_2">异常</h2>
<p>即使语句或表达式在语法上是正确的，执行时也可能会引发错误。运行期检测到的错误称为异常</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="mi">10</span> <span class="o">*</span> <span class="p">(</span><span class="mi">1</span><span class="o">/</span><span class="mi">0</span><span class="p">)</span>
<span class="n">Traceback</span> <span class="p">(</span><span class="n">most</span> <span class="n">recent</span> <span class="n">call</span> <span class="n">last</span><span class="p">):</span>
<span class="n">File</span> <span class="s2">"<stdin>"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">1</span><span class="p">,</span> <span class="ow">in</span> <span class="o"><</span><span class="n">module</span><span class="o">></span>
<span class="ne">ZeroDivisionError</span><span class="p">:</span> <span class="n">division …</span></pre></div>
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<h1><a href="/python3_crash9.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程3文本处理1正则表达式">[雪峰磁针石博客]python3快速入门教程3文本处理1正则表达式</a></h1>
</header>
<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:45:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">简介</h2>
<p>-- 后面有很多习题，可以先做题目再来看文章</p>
<p>参考资料：https://docs.python.org/3/howto/index.html</p>
<p>正则表达式(Regular expressions REs或regexes或regex patterns）本质是小的且高度专业化的编程语言。它嵌入到 Python 中，调用使用re模块。需要指定一些规则来描述那些你希望匹配的字符串集合。这些字符串集合可能包含英语句子、e-mail地址、TeX 命令，或任何你想要的东东。然后可以提出问题，例如“字符串是否匹配该模式？”或“模式是否匹配字符串？”。 您还可以使用RE修改字符串或以各种方式拆分它。</p>
<p>正则表达式模式被编译成字节码，然后由 C 语言写的匹配引擎执行。对于高级的使用，你可能需要关注匹配引擎是如何执行给定RE，并通过一定的方式来编写RE，以便产生运行得更快的字节码。</p>
<p>正则表达式语言小而严格，不是所有的字符处理都可以使用正则表达式。还有一些任务，可以使用正则表达式来完成，但是表达式非常复杂。在这种情况下编写 Python 代码来处理会更好些 …</p>
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<h1><a href="/python3_crash8.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程2数据结构4其他数据结构">[雪峰磁针石博客]python3快速入门教程2数据结构4其他数据结构</a></h1>
</header>
<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:40:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">数据结构</h2>
<h4 id="_2">函数式编程工具</h4>
<p>对于列表来讲，有三个内置函数非常有用: filter(), map(), 以及reduce()。 </p>
<p>filter(function, sequence)返回function(item)为true的子序列。会尽量返回和sequence相同的类型）。sequence是string或者tuple时返回相同类型，其他情况返回list 。实例：返回能被3或者5整除的序列: </p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="k">def</span> <span class="nf">f</span><span class="p">(</span><span class="n">x</span><span class="p">):</span> <span class="k">return</span> <span class="n">x</span> <span class="o">%</span> <span class="mi">3</span> <span class="o">==</span> <span class="mi">0</span> <span class="ow">or</span> <span class="n">x</span> <span class="o">%</span> <span class="mi">5</span> <span class="o">==</span> <span class="mi">0</span>
<span class="o">...</span>
<span class="o">>>></span> <span class="nb">list</span><span class="p">(</span><span class="nb">filter</span><span class="p">(</span><span class="n">f</span><span class="p">,</span> <span class="nb">range</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">25</span><span class="p">)))</span>
<span class="p">[</span><span class="mi">3</span><span class="p">,</span> <span class="mi">5</span><span class="p">,</span> <span class="mi">6</span><span class="p">,</span> <span class="mi">9</span><span class="p">,</span> <span class="mi">10</span><span class="p">,</span> <span class="mi">12</span><span class="p">,</span> <span class="mi">15</span><span class="p">,</span> <span class="mi">18</span><span class="p">,</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">21</span><span class="p">,</span> <span class="mi">24</span><span class="p">]</span>
</pre></div>
<p>map(function, sequence) 为每个元素调用 …</p>
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<h1><a href="/python3_crash_ch7.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程7输入和输出">[雪峰磁针石博客]python3快速入门教程7输入和输出</a></h1>
</header>
<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:40:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <p>python有多种输出方式：屏幕打印数据，或者写入文件。</p>
<h2 id="_1">格式化输出</h2>
<p>我们有两种大相径庭地输出值方法：表达式语句* 和 <a href="https://docs.python.org/3/library/functions.html#print">print()</a> 函数(第三种方法使用文件对象的write()方法，标准文件输出可以参考sys.stdout)。</p>
<p>通常需要对输出做更多的格式控制，而不是简单的打印空格分隔值。有两种方法可以格式化你的输出：第一种方法是由你自己处理整个字符串，通过使用字符串切片和连接操作可以创建任何你想要的输出形式。string 类型包含一些将字符串填充到指定列宽度的有用操作。第二种方法是使用 <a href="https://docs.python.org/3/library/stdtypes.html#str.format">str.format()</a> 方法。</p>
<p>标准模块 <a href="https://docs.python.org/3/library/string.html#module-string">string</a> 的<a href="https://docs.python.org/3/library/string.html#string.Template">Template</a> 类可以替换字符串的值。(<a href="https://china-testing.github.io/python3_lib_string.html">python标准模块介绍-string:文本常量和模板</a>)</p>
<p>Python 有办法将任意值转为字符串： <a href="https://docs.python.org/3/library/functions.html#repr">repr()</a> 或 <a href="https://docs.python.org/3/library/stdtypes.html#str">str()</a> 函数。</p>
<p>函数 <a href="https://docs.python.org/3/library/stdtypes.html#str">str()</a> 用于将值转化为适于人阅读的形式，而 <a href="https://docs.python.org/3/library/functions.html#repr">repr()</a> 转化为供解释器读取的形式（如果没有相关语法，则会发生 <a href="https://docs.python.org/3/library/exceptions.html#SyntaxError">SyntaxError</a> 异常，没有<a href="https://docs.python.org/3/library/stdtypes.html#str">str()</a> 会返回与 …</p>
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title="Permalink to [雪峰磁针石博客]python3快速入门教程2数据结构2字符串">[雪峰磁针石博客]python3快速入门教程2数据结构2字符串</a></h1>
</header>
<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:35:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">快速入门</h2>
<p>字符串可以包含在单引号或双引号中。</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="s1">'spam eggs'</span> <span class="c1"># single quotes</span>
<span class="s1">'spam eggs'</span>
<span class="o">>>></span> <span class="s1">'doesn</span><span class="se">\'</span><span class="s1">t'</span> <span class="c1"># use \' to escape the single quote...</span>
<span class="s2">"doesn't"</span>
<span class="o">>>></span> <span class="s2">"doesn't"</span> <span class="c1"># ...or use double quotes instead</span>
<span class="s2">"doesn't"</span>
<span class="o">>>></span> <span class="s1">'"Yes," he said.'</span>
<span class="s1">'"Yes," he said.'</span>
<span class="o">>>></span> <span class="s2">"</span><span class="se">\"</span><span class="s2">Yes,</span><span class="se">\"</span><span class="s2"> he said."</span>
<span class="s1">'"Yes," he said.'</span>
<span class="o">>>></span> <span class="s1">'"Isn</span><span class="se">\'</span><span class="s1">t," she said.'</span>
<span class="s1">'"Isn</span><span class="se">\'</span><span class="s1">t," she said.'</span>
</pre></div>
<p>解释器按照字符串被输入的方式显示字符串，通常包含在单引号中，如果内容包含包含单引号 …</p>
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<h1><a href="/python3_crash7.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程2数据结构3列表">[雪峰磁针石博客]python3快速入门教程2数据结构3列表</a></h1>
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<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:35:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">快速入门</h2>
<p>Python有一些复合数据类型，用于组合值。最常用的是 list(列表))，为中括号之间的逗号分隔的值。列表的元素可以是多种类型，但是通常是同一类型。</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="n">squares</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">9</span><span class="p">,</span> <span class="mi">16</span><span class="p">,</span> <span class="mi">25</span><span class="p">]</span>
<span class="o">>>></span> <span class="n">squares</span>
<span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">9</span><span class="p">,</span> <span class="mi">16</span><span class="p">,</span> <span class="mi">25</span><span class="p">]</span>
</pre></div>
<p>像字符串和其他序列类型，列表可支持切片和索引:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="n">squares</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="c1"># indexing returns the item</span>
<span class="mi">1</span>
<span class="o">>>></span> <span class="n">squares</span><span class="p">[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span>
<span class="mi">25</span>
<span class="o">>>></span> <span class="n">squares</span><span class="p">[</span><span class="o">-</span><span class="mi">3</span><span class="p">:]</span> <span class="c1"># slicing returns a new list</span>
<span class="p">[</span><span class="mi">9</span><span class="p">,</span> <span class="mi">16</span><span class="p">,</span> <span class="mi">25</span><span class="p">]</span>
</pre></div>
<p>切片返回新的列表，下面操作返回列表a的浅拷贝:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="n">squares</span><span class="p">[:]</span>
<span class="p">[</span><span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">,</span> <span class="mi">9</span><span class="p">,</span> <span class="mi">16 …</span></pre></div>
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<h1><a href="/python3_crash5.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程2数据结构1变量与赋值">[雪峰磁针石博客]python3快速入门教程2数据结构1变量与赋值</a></h1>
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<div class="entry-content">
<footer class="post-info">
<abbr class="published" title="2018-09-02T10:30:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">语法基础</h2>
<p>解释器像简单的计算器：可以输入表达式，它会返回值。表达式语法很简单：运算符 + ， - ， * 和 / 与其它语言一样(例如Pascal或C)；括号用于分组。例如:</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="mi">2</span> <span class="o">+</span> <span class="mi">2</span>
<span class="mi">4</span>
<span class="o">>>></span> <span class="mi">50</span> <span class="o">-</span> <span class="mi">5</span><span class="o">*</span><span class="mi">6</span>
<span class="mi">20</span>
<span class="o">>>></span> <span class="p">(</span><span class="mi">50</span> <span class="o">-</span> <span class="mf">5.0</span><span class="o">*</span><span class="mi">6</span><span class="p">)</span> <span class="o">/</span> <span class="mi">4</span>
<span class="mf">5.0</span>
<span class="o">>>></span> <span class="mi">8</span> <span class="o">/</span> <span class="mf">5.0</span>
<span class="mf">1.6</span>
</pre></div>
<p>整数(例如2、4、20 )的类型是 int，带有小数部分的数字(例如5.0、1.6)的类型是 float。</p>
<p>除法(/)永远返回浮点数。地板除使用 // 运算符；要计算余数你可以使用 %。</p>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="mi">17</span> <span class="o">/</span> <span class="mi">3 …</span></pre></div>
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<h1><a href="/python3_crash4.html" rel="bookmark"
title="Permalink to [雪峰磁针石博客]python3快速入门教程1 turtle绘图-4选择与随机数">[雪峰磁针石博客]python3快速入门教程1 turtle绘图-4选择与随机数</a></h1>
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<abbr class="published" title="2018-09-02T10:25:00+08:00">
Published: 日 02 九月 2018
</abbr>
<address class="vcard author">
By <a class="url fn" href="/author/andrew.html">andrew</a>
</address>
<p>In <a href="/category/python.html">python</a>.</p>
</footer><!-- /.post-info --> <h2 id="_1">语法</h2>
<h3 id="if">if语句</h3>
<div class="highlight"><pre><span></span><span class="o">>>></span> <span class="n">x</span> <span class="o">=</span> <span class="nb">int</span><span class="p">(</span><span class="nb">input</span><span class="p">(</span><span class="s2">"Please enter an integer: "</span><span class="p">))</span>
<span class="n">Please</span> <span class="n">enter</span> <span class="n">an</span> <span class="n">integer</span><span class="p">:</span> <span class="mi">42</span>
<span class="o">>>></span> <span class="k">if</span> <span class="n">x</span> <span class="o"><</span> <span class="mi">0</span><span class="p">:</span>
<span class="o">...</span> <span class="n">x</span> <span class="o">=</span> <span class="mi">0</span>
<span class="o">...</span> <span class="k">print</span><span class="p">(</span><span class="s1">'Negative changed to zero'</span><span class="p">)</span>
<span class="o">...</span> <span class="k">elif</span> <span class="n">x</span> <span class="o">==</span> <span class="mi">0</span><span class="p">:</span>
<span class="o">...</span> <span class="k">print</span><span class="p">(</span><span class="s1">'Zero'</span><span class="p">)</span>
<span class="o">...</span> <span class="k">elif</span> <span class="n">x</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="o">...</span> <span class="k">print</span><span class="p">(</span><span class="s1">'Single'</span><span class="p">)</span>
<span class="o">...</span> <span class="k">else</span><span class="p">:</span>
<span class="o">...</span> <span class="k">print</span><span class="p">(</span><span class="s1">'More'</span><span class="p">)</span>
<span class="o">...</span>
<span class="n">More</span>
</pre></div>
<p>可能会有零到多个elif部分，else是可选的。关键字‘elif‘是‘else if’的缩写，可避免过深的缩进。 if ... elif ... elif序列用于替代其它语言中的switch或case语句 …</p>
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