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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title><![CDATA[葱丝瓣酱]]></title>
<link href="http://xiaocong.github.io/atom.xml" rel="self"/>
<link href="http://xiaocong.github.io/"/>
<updated>2014-03-02T21:42:17+08:00</updated>
<id>http://xiaocong.github.io/</id>
<author>
<name><![CDATA[Xiaocong He]]></name>
<email><![CDATA[[email protected]]]></email>
</author>
<generator uri="http://octopress.org/">Octopress</generator>
<entry>
<title type="html"><![CDATA[Android uiautomator的python包]]></title>
<link href="http://xiaocong.github.io/blog/2013/08/26/android-uiautomator-and-python/"/>
<updated>2013-08-26T17:59:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/08/26/android-uiautomator-and-python</id>
<content type="html"><![CDATA[<p>随着Android的快速演进，先后经历了 Android 测试框架从 InstrumentationTest, Robotium, Monkeyrunner, 直到 uiautomator 的变化，从目前来看，对于独立的QA团队来说，uiautomator 是最适合的 Android 测试框架.</p>
<p>就我个人的体会，沉重的 Java 语言及其繁琐的工具链，是阻碍 uiautomator 推广的障碍，个人更喜欢 Python 和 Javascript 的快速开发和方便的工具链。为了更方便地利用 uiautomator，花了两周时间实现了 Android uiautomator 的 Python Wrapper 模块并开源出来：</p>
<ul>
<li><a href="https://pypi.python.org/pypi/uiautomator">pypi: uiautomator</a></li>
<li><a href="http://xiaocong.github.io/slides/android-uiautomator-and-python/">uiautomator.py slides</a></li>
<li><a href="https://github.com/xiaocong/uiautomator">github source code</a></li>
</ul>
<p>希望下一步能有时间完成相应的 nodejs 模块。</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[符合语言习惯的Python编程]]></title>
<link href="http://xiaocong.github.io/blog/2013/07/18/idiomatic-python-code/"/>
<updated>2013-07-18T12:02:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/07/18/idiomatic-python-code</id>
<content type="html"><![CDATA[<p>给 Team 内部培训用的 Slides：<a href="http://xiaocong.github.io/slides/idiomatic-python-code/">符合语言习惯的Python编程</a></p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[在Ubuntu下配置舒服的Python开发环境]]></title>
<link href="http://xiaocong.github.io/blog/2013/06/18/customize-python-dev-environment-on-ubuntu/"/>
<updated>2013-06-18T14:37:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/06/18/customize-python-dev-environment-on-ubuntu</id>
<content type="html"><![CDATA[<p>Ubuntu 提供了一个良好的 Python 开发环境，但如果想使我们的开发效率最大化，还需要进行很多定制化的安装和配置。下面的是我们团队开发人员推荐的一个安装和配置步骤，基于 Ubuntu 12.04 桌面版本标准安装。</p>
<h2>安装 Python 发布版本和 build 依赖包</h2>
<p>建议至少安装 Python 2.7/3.2 版本，毕竟 Python 2.X/3.X 还是有不少区别的。</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="c"># 安装 Python 发布版本，dev包必须安装，很多用pip安装包都需要编译</span>
</span><span class='line'>sudo apt-get install python2.7 python2.7-dev python3.2 python3.2-dev
</span><span class='line'><span class="c"># 很多pip安装的包都需要libssl和libevent编译环境</span>
</span><span class='line'>sudo apt-get install build-essential libssl-dev libevent-dev libjpeg-dev libxml2-dev libxslt-dev
</span></code></pre></td></tr></table></div></figure>
<!--more-->
<h2>安装 pip 和 virtualenv</h2>
<p><code>pip</code> 是 Python 的包管理工具，建议 Python 的包都用 pip 进行管理。<code>virtualenv</code>是 Python 多版本管理的利器，不同版本的开发调试全靠它了。</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="c"># 安装 pip</span>
</span><span class='line'>sudo apt-get install python-pip
</span><span class='line'><span class="c"># 安装 virtualenv</span>
</span><span class='line'>sudo pip install virtualenv
</span></code></pre></td></tr></table></div></figure>
<h2>配置个人用 virtualenv</h2>
<p>尽量在 virtualenv 下进行 Python 包的安装。</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="c"># 安装 python2.7 virtualenv</span>
</span><span class='line'>virtualenv --no-site-packages -p /usr/bin/python2.7 ~/.venv/python2.7
</span><span class='line'>
</span><span class='line'><span class="c"># 安装 python3.2 virtualenv</span>
</span><span class='line'>virtualenv --no-site-packages -p /usr/bin/python3.2 ~/.venv/python3.2
</span></code></pre></td></tr></table></div></figure>
<p>然后将下面的代码增加到<code>~/.bashrc</code>的最后面，缺省使用 virtualenv 来代替系统 Python 环境：</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="c"># 缺省激活python2.7环境</span>
</span><span class='line'><span class="k">if</span> <span class="o">[</span> -f ~/.venv/python2.7/bin/activate <span class="o">]</span>; <span class="k">then</span>
</span><span class='line'> . ~/.venv/python2.7/bin/activate
</span><span class='line'><span class="k">fi</span>
</span></code></pre></td></tr></table></div></figure>
<h2>安装 git 和 gitflow</h2>
<p><code>git</code>是使用 github 必备，目前最好的版本管理工具。</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="nv">$ </span>sudo apt-get install git
</span></code></pre></td></tr></table></div></figure>
<p>配置 git：</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="c"># 常用的命令都设置alias，尽量少敲键盘</span>
</span><span class='line'>git config --global alias.br branch
</span><span class='line'>git config --global alias.ci commit
</span><span class='line'>git config --global alias.co checkout
</span><span class='line'>git config --global alias.st status
</span><span class='line'><span class="c"># 很好看地显示git log</span>
</span><span class='line'>git config --global alias.lg <span class="s2">"log --color --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen (%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --"</span>
</span><span class='line'><span class="c"># 设置用户信息</span>
</span><span class='line'>git config --global user.name <span class="s2">"Your Name"</span>
</span><span class='line'>git config --global user.email [email protected]
</span><span class='line'><span class="c"># 缺省使用颜色显示</span>
</span><span class='line'>git config --global color.ui <span class="nb">true</span>
</span></code></pre></td></tr></table></div></figure>
<p>安装 <code>git-flow</code>，使用标准化 git 分支流程，参见：</p>
<ul>
<li><a href="http://jeffkreeftmeijer.com/2010/why-arent-you-using-git-flow/">使用 Git Flow</a></li>
<li><a href="http://nvie.com/posts/a-successful-git-branching-model/">一个成功的 Git 分支模型</a></li>
</ul>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'>sudo apt-get install git-flow
</span></code></pre></td></tr></table></div></figure>
<h2>安装 bash-it</h2>
<p><code>bash-it</code>可以美化你的 bash 环境，让你更高效地使用控制台终端，详细信息参见<a href="https://github.com/revans/bash-it">bash-it github 网站</a></p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'>git clone http://github.com/revans/bash-it.git ~/.bash_it
</span><span class='line'>~/.bash_it/install.sh
</span></code></pre></td></tr></table></div></figure>
<p>安装的时候可以选择所有的 alias/plugins/completion，如果自定义选择，一定将<code>virtualenv</code>, <code>git</code>插件选择上。</p>
<p>安装完成后将下面的代码附加到<code>~/.bashrc</code>的后面：</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="k">if</span> <span class="o">[</span> -f ~/.bash_profile <span class="o">]</span>; <span class="k">then</span>
</span><span class='line'> . ~/.bash_profile
</span><span class='line'><span class="k">fi</span>
</span></code></pre></td></tr></table></div></figure>
<p><code>bash-it</code>安装完成后缺省使用 bobby 样式(可以参见<code>~/.bash_profile</code>里定义的环境变量<code>BASH_IT_THEME</code>)，编辑<code>~/.bash_it/themes/bobby/bobby.theme.bash</code>，在<code>PS1</code>的定义里增加<code>${green}$(virtualenv_prompt)</code>，如下：</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'><span class="nv">PS1</span><span class="o">=</span><span class="s2">"\n${yellow}$(ruby_version_prompt)${green}$(virtualenv_prompt) ${purple}\h ${reset_color}in ${green}\w\n${bold_cyan}$(scm_char)${green}$(scm_prompt_info) ${green}→${reset_color} "</span>
</span></code></pre></td></tr></table></div></figure>
<p>注：样式定义参加文件<code>~/.bash_profile</code>里定义的环境变量<code>BASH_IT_THEME</code>，你也将其值更改成其他<code>~/.bash_it/themes</code>里定义的样式。</p>
<p>最后重启终端，你将看到一个不一样的<code>bash</code>，支持显示<code>git</code>分支，<code>virtualenv</code>，<code>rvm</code>等。</p>
<h2>安装 Sublime Text 2</h2>
<p>在浏览器进入 <a href="http://www.sublimetext.com/2">Sublime Text 2 官网</a>，选择适合的版本下载安装。</p>
<p>安装完成后还需要安装<code>Sublime Text 2</code>的<code>Package Control</code>。安装细节参见 <a href="http://wbond.net/sublime_packages/package_control/installation">Sublime Packages 安装</a>。</p>
<p>最后，按快捷键<code>Ctrl+Shift+P</code>调出命令窗口，选择<code>Package Control: Install Package</code>，安装 Python 开发常用的插件：</p>
<ul>
<li>Auto Encoding for Python</li>
<li>BracketHighlighter</li>
<li>Git</li>
<li>Markdown Preview</li>
<li>Python Auto-Complete</li>
<li>SublimeLinter</li>
<li>SidebarEnhancements</li>
<li>SublimeCondeIntel</li>
<li>sublime-github</li>
<li>Dayle Rees Color Schemes</li>
</ul>
<p>这里推荐一下插件 sublime-github，能在 Sublime 里查看，增加，修改<a href="https://gist.github.com">GitHub Gist</a>。如果你和团队都使用 Github Gist 来存储自己常用的代码片段，这将非常方便大家去迅速查找和共享解决常见问题的代码片段。</p>
<ul>
<li>首先进入<a href="https://github.com/settings/applications">github</a> 新建一个个人 API 访问 token；</li>
<li>运行 Sublime，选择菜单<code>Preferences</code>–><code>Package Settings</code>–><code>GitHub</code>–><code>Settings-Default</code>，将上面生成的<code>token</code>复制到
<code>github_token</code>字段，保存。</li>
</ul>
<p>之后你就可以按快捷键<code>Ctrl+Shift+P</code>，选择<code>GitHub: Open Gist in Editor</code>，然后选择你自己的 Gist 即可。</p>
<h2>安装并配置 Vim</h2>
<p>有了 Sublime Text，大部分情况下都不需要 Vi 了，但的确有些时候进行很小的改动还是用 Vi 最方便。Ubuntu的缺省安装应当已经包括了 Vim，如果没有，运行下面命令安装 Vim。</p>
<figure class='code'><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
</pre></td><td class='code'><pre><code class='bash'><span class='line'>sudo apt-get install vim
</span></code></pre></td></tr></table></div></figure>
<p>然后，参考<a href="https://github.com/amix/vimrc">Amix’s Vimrc</a>来配置 Vim。</p>
<hr />
<p>至此，所有的基本环境就已经配备完成，希望这些配置能对大家有所帮助，下面是配置好的界面截屏。</p>
<p><img src="http://xiaocong.github.io/images/post/bash.png"></p>
<p><img src="http://xiaocong.github.io/images/post/sublime.png"></p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[Python 面试问题]]></title>
<link href="http://xiaocong.github.io/blog/2013/06/16/python-interview-question-and-answer/"/>
<updated>2013-06-16T12:36:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/06/16/python-interview-question-and-answer</id>
<content type="html"><![CDATA[<p>最近正在团队内部普及 Python 语言，有些刚接触 Python 语言的工程师在概念上有很多混淆的地方，刚好看到这篇文章:<a href="http://ilian.i-n-i.org/python-interview-question-and-answers/">Python面试问题</a>，里面列举的问题都是关于 Python 基本的常识或者容易混淆的知识点，因此推荐给团队的 Python 初学者。</p>
<!--more-->
<ol>
<li><p>参数是如何传递的？传值还是传引用？(How are arguments passed – by reference of by value?)</p>
<p>这个问题的有点c/c++风格，问题的实质是当一个传入的参数在函数体内被更改，那么在函数返回后，函数体外的这个参数变量的值是否改变。最简短的回答是，”都不是”，事实上 Python 里是传对象(call by object)。</p>
<p>要弄明白这个变量的值是否在函数体外发生变化，需要明白两个概念：</p>
<ul>
<li>Python 里的对象分为有可变(mutable)和不可变(immutable)：数字(int, float)，字符串，元组(tuple)是不可变的，列表(list)，字典(dict)是可变的。</li>
<li>所有的变量都是一个对象的引用。无论对象是否可变，这个变量都可被赋值为另外一个对象。</li>
</ul>
<p>因此，如果传入的参数变量指向一个不可变对象，那么在函数体外这个对象的内容永远不会发生变化；如果当传入的参数变量指向一个可变对象，那么这个对象是否发生变化，取决于函数体内部是否改变了这个可变对象的内容。</p>
<p>下面的例子里，<code>changed</code>函数调用改变了传入对象的内容，<code>unchanged</code>函数将<code>l</code>变量赋值为一个新生成的对象<code>l = l + ["a"]</code>，但原始对象并未发生变化：</p>
<pre><code>def changed(l):
l.append("a") # change the original object
def unchanged(l):
l = l + ["a"] # l + ["a"] will create a new list, instead of changing the original object
l1 = []
changed(l1)
# l1 == ["a"]
l2 = []
unchanged(l2)
# l2 == []
</code></pre></li>
<li><p>什么是列表和字典推导(list and dict comprehensions)？你能给个例子吗？</p>
<p>列表/字典推导是一种语法糖(syntax sugar)，用来简化列表和字典的生成。根据第三版的”Learning Python”，列表推导的执行速度快于通常的循环，但并不确保以后的 Python 版本也是这个结果。</p>
<pre><code># simple iteration
a = []
for x in range(10):
a.append(x*2)
# a == [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
# list comprehension
a = [x*2 for x in range(10)]
# dict comprehension
a = {x: x*2 for x in range(10)}
# a == {0: 0, 1: 2, 2: 4, 3: 6, 4: 8, 5: 10, 6: 12, 7: 14, 8: 16, 9: 18
# set comprehension
a = {x**2 for x in range(10) if x % 2 == 0}
# a == set([0, 16, 4, 64, 36])
</code></pre>
<p><strong>列表推导是典型的 Pythonic 的代码书写方式。</strong></p></li>
<li><p>什么是 PEP 8？</p>
<p>PEP 8 定义的是 Python 代码规范，告诉你如何书写可读性强，更好维护的代码。详细内容请参考<a href="http://www.python.org/dev/peps/pep-0008/">PEP 8 官方文档</a>。Sublime Text编辑工具带有 PEP 8 格式检测插件，所存盘的文件都应当符合 PEP 8 的规范。</p></li>
<li><p>你使用虚拟环境(virtual environment)吗？</p>
<p>很多 Python 程序员认为，包括我自己也是这样的观点，<a href="https://pypi.python.org/pypi/virtualenv">virtual environment</a>是一个非常有用的工具，用来孤立你的开发和运行环境，特别是当需要同时开发多个项目，基于不同的 Python 版本以及运行库的时候。每当新建一个项目，或者clone一个已存在项目的时候，我都会按照下面的步骤建立和使用虚拟环境：</p>
<pre><code># create virtual env
virtualenv --no-site-packages --python=python3.2 ./venv
# activate virtual env
source ./venv/bin/activate
# install requirements
pip install -r requirements.txt
#.....
# update requirements
pip freeze > requirements.txt
</code></pre></li>
<li><p>如何计算列表里所有元素的和？如何计算列表里所有元素的乘积？</p>
<p>这个问题相当简单，但需要记住一点，你需要用 Pythonic 的方式来解答这个问题：</p>
<pre><code># 计算列表内所有元素的和, 包括基本loop方式，sum函数方式，以及使用reduce函数
# the basic way
s = 0
for x in range(10):
s += x
# the right way
s = sum(range(10))
# the other way
from operator import add
s = reduce(add, range(10))
# 计算列表内所有元素的乘积
# the basic way
s = 1
for x in range(1, 10):
s = s * x
# the other way
from operator import mul
reduce(mul, range(1, 10))
</code></pre></li>
<li><p>你能列出列表(list)和元组(tuple)的区别吗？举例子说明用法的不同。</p>
<p>列表和元组是 Python 里最基本的两个数据类型：</p>
<ul>
<li>首先，列表对象是可变的(mutable)，但元组不是；</li>
<li>其次，元组可被哈希(hashed)，例如可以用作字典对象的键值(key)；</li>
</ul>
<p>至于例子，地图上的地理坐标可以用二元组表示，而地图上的路径可以用坐标点列表来表示。</p></li>
<li><p>你知道<code>range</code>和<code>xrange</code>的区别吗？</p>
<p><code>range</code>函数返回的是一个列表对象，<code>xrange</code>返回的是一个<code>xrange</code>对象。他们的主要区别是：</p>
<ul>
<li>内存的占用不同。列表对象已经在内存中存在了，而<code>xrange</code>对象永远占
用同样的内存大小，无论需要生成的<code>range</code>有多大。</li>
<li><code>xrange</code>对象不能使用列表对象的切片函数，也就是说
<code>range(10)[3:5]</code>能工作，但是<code>xrange(10)[3:5]</code>就不工作了。</li>
</ul>
<p>类似的问题还有：<code>map</code>和<code>itertools.imap</code>的区别？<code>filter</code>和<code>itertools.ifilter</code>的区别？清楚这些区别，你就能知道怎样更有效地使用这些函数。</p></li>
<li><p>请说出一些 python2.x 与 python3.x 之间的区别。</p>
<p>如果你经常看网上的文章，你肯定能说出一些区别：</p>
<ul>
<li>python3.x 的字符串都是unicode；</li>
<li>python3.x 中<code>print</code>是函数，而不是语句；</li>
<li>python3.x 中使用<code>range</code>代替了<code>xrange</code>，删除了<code>xrange</code>函数；</li>
<li>python3.x 中全部类(class)都是新类型(new style)；</li>
<li>python3.x 支持更简单的<code>unpack</code>方式，如<code>first, *middle, last = [0, 1, 2, 3, 4, 5, 6, 7]</code></li>
</ul>
<p>如果你一条区别也说不出来，至少说明你对 Python 的关注度不够。</p></li>
<li><p>什么是修饰器(Decorator)？你能说出它的用途吗？</p>
<p>修饰器(Decorator)也是一种非常 Pythonic 的方式，它可以让你非常方便地注入(inject)或者修改函数和类的代码。换句话说，修饰器允许你包装函数和类方法，在执行原始代码之前和之后执行其他的代码。修饰器语法能带来很多非常有意思的编码方式，例如：</p>
<ul>
<li><p>内存缓存</p>
<pre><code> def memoize(f):
memo = {} # 将结果缓存在memo字典对象中，key是参数，value是结果。
def helper(x):
if x not in memo:
memo[x] = f(x)
return memo[x]
return helper
# 修饰fib函数，任何fib函数的调用，将首先察看是否已经有缓存的结果
@memoize
def fib(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return fib(n-1) + fib(n-2)
print(fib(40)) # 102334155
</code></pre></li>
<li><p>参数检测</p>
<pre><code> def argument_test_natural_number(f):
def helper(x):
if type(x) == int and x > 0:
return f(x)
else:
raise Exception("Argument is not an integer")
return helper
@argument_test_natural_number
def faculty(n):
if n == 1:
return 1
else:
return n * faculty(n-1)
for i in range(1,10):
print(i, faculty(i))
# 1 1
# 2 2
# 3 6
# 4 24
# 5 120
# 6 720
# 7 5040
# 8 40320
# 9 362880
faculty(-1) # 使用非法的参数调用faculty函数，这将raise一个exception
# Exception: Argument is not an integer
</code></pre></li>
</ul>
</li>
<li><p> <code>with</code>语句及其用法？</p>
<p>简单地说，<code>with</code>语句允许你在进入和/或退出指定的代码块的时候，执行特定的代码。最常用的例子是使用<code>with</code>句打开文件。为了在你自己定义的对象上使用<code>with</code>语句，你必须定义<code>__enter__</code>和<code>__exit__</code>方法。</p>
<p>更多的信息你可以查看<a href="http://effbot.org/zone/python-with-statement.htm">理解 Python 的 with 语句</a>。</p></li>
</ol>
<hr />
<p>除了原文列举上述问题，下面知识点也是 Python 面试中很可能被问到的：</p>
<ul>
<li>Package/Module的定义，以及模块加载原则；</li>
<li>如何构建你自己的类型，如列表(list)，字典(dict)，迭代器(iterator)；</li>
<li>生成器(generator)的概念以及使用方式；</li>
<li>built-in 类型和函数；</li>
<li>对象属性的操作原理，如<strong>dict</strong>，<strong>getattr</strong>，<strong>getattribute</strong>，描述
器(descriptor)；</li>
<li>元类编程(metaclass)的概念，以及如何使用；</li>
<li>如何进行Package/Module的打包和分发；</li>
<li>什么是WSGI；</li>
<li>字符串的处理和正则表达式；</li>
<li>如何操作json和xml数据；</li>
</ul>
<p>另外，还必须尽可能地多了解 Python 语言最为强大的
<a href="http://docs.python.org/2/library/">库函数</a>。</p>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[在Python中生成单体实例的方法]]></title>
<link href="http://xiaocong.github.io/blog/2013/06/04/creating-a-singleton-in-python/"/>
<updated>2013-06-04T10:53:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/06/04/creating-a-singleton-in-python</id>
<content type="html"><![CDATA[<p>Python是很强力的编程语言，它即支持面向对象编程的特征，也支持很多函数式编程的特征，同时还是一门动态语言。由于Python语言特征的多样性，对于同一种设计需求，我们可以采用多种完全不同的方式进行实现。优秀的软件工程师总能在这些实现方式中，根据他们的优劣，选择出最适合的方式。</p>
<p>下面的内容源自<a href="http://stackoverflow.com/">StackOverflow</a>的一篇文章：<a href="http://stackoverflow.com/questions/6760685/creating-a-singleton-in-python">Creating a singleton in python</a>
。</p>
<blockquote><p>这个问题不是为了讨论单体实例是否是有必要的，或者是反面模式，也不是为了挑起任何宗教式的战争，而是为了讨论如何用更Pythonic的方式，最佳地实现单体实例模式。</p></blockquote>
<!--more-->
<h2>方法1：装饰器(Decorator)</h2>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="k">def</span> <span class="nf">singleton</span><span class="p">(</span><span class="n">class_</span><span class="p">):</span>
</span><span class='line'> <span class="n">instances</span> <span class="o">=</span> <span class="p">{}</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">getinstance</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
</span><span class='line'> <span class="k">if</span> <span class="n">class_</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">instances</span><span class="p">:</span>
</span><span class='line'> <span class="n">instances</span><span class="p">[</span><span class="n">class_</span><span class="p">]</span> <span class="o">=</span> <span class="n">class_</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</span><span class='line'> <span class="k">return</span> <span class="n">instances</span><span class="p">[</span><span class="n">class_</span><span class="p">]</span>
</span><span class='line'> <span class="k">return</span> <span class="n">getinstance</span>
</span><span class='line'>
</span><span class='line'><span class="nd">@singleton</span>
</span><span class='line'><span class="k">class</span> <span class="nc">MyClass</span><span class="p">(</span><span class="n">BaseClass</span><span class="p">):</span>
</span><span class='line'> <span class="k">pass</span>
</span><span class='line'>
</span><span class='line'><span class="n">c</span> <span class="o">=</span> <span class="n">MyClass</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
<p><strong>优点</strong></p>
<ul>
<li>装饰器在通常情况下比其他任何方式都要直观。</li>
</ul>
<p><strong>缺点</strong></p>
<ul>
<li>任何通过调用<code>MyClass()</code>能获得真的单体实例，但是<code>MyClass</code>本身却被装饰成一个函数(function)了，也就是说不能使用任何类方法和与类相关的函数如<code>isinstance</code>，<code>issubclass</code>等。</li>
<li>还能从<code>MyClass</code>继承一个子类么？</li>
</ul>
<h2>方法2：基类继承</h2>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="k">class</span> <span class="nc">Singleton</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
</span><span class='line'> <span class="n">_instances</span> <span class="o">=</span> <span class="p">{}</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">__new__</span><span class="p">(</span><span class="n">class_</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
</span><span class='line'> <span class="k">if</span> <span class="n">class_</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">class_</span><span class="o">.</span><span class="n">_instances</span><span class="p">:</span>
</span><span class='line'> <span class="n">class_</span><span class="o">.</span><span class="n">_instances</span><span class="p">[</span><span class="n">class_</span><span class="p">]</span> <span class="o">=</span> <span class="nb">super</span><span class="p">(</span><span class="n">Singleton</span><span class="p">,</span> <span class="n">class_</span><span class="p">)</span><span class="o">.</span><span class="n">__new__</span><span class="p">(</span><span class="n">class_</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</span><span class='line'> <span class="k">return</span> <span class="n">class_</span><span class="o">.</span><span class="n">_instances</span><span class="p">[</span><span class="n">class_</span><span class="p">]</span>
</span><span class='line'>
</span><span class='line'><span class="k">class</span> <span class="nc">MyClass</span><span class="p">(</span><span class="n">Singleton</span><span class="p">,</span> <span class="n">BaseClass</span><span class="p">):</span> <span class="c"># 这里Singleton必须放在其他基类前面</span>
</span><span class='line'> <span class="k">pass</span>
</span><span class='line'>
</span><span class='line'><span class="n">c</span> <span class="o">=</span> <span class="n">MyClass</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
<p><strong>优点</strong></p>
<ul>
<li><code>MyClass</code>是真的类(class)。</li>
</ul>
<p><strong>缺点</strong></p>
<ul>
<li>多继承…得小心使用！</li>
</ul>
<h2>方法3：元类(Metaclass)</h2>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="k">class</span> <span class="nc">Singleton</span><span class="p">(</span><span class="nb">type</span><span class="p">):</span>
</span><span class='line'> <span class="n">_instances</span> <span class="o">=</span> <span class="p">{}</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
</span><span class='line'> <span class="k">if</span> <span class="n">cls</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">cls</span><span class="o">.</span><span class="n">_instances</span><span class="p">:</span>
</span><span class='line'> <span class="n">cls</span><span class="o">.</span><span class="n">_instances</span><span class="p">[</span><span class="n">cls</span><span class="p">]</span> <span class="o">=</span> <span class="nb">super</span><span class="p">(</span><span class="n">Singleton</span><span class="p">,</span> <span class="n">cls</span><span class="p">)</span><span class="o">.</span><span class="n">__call__</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</span><span class='line'> <span class="k">return</span> <span class="n">cls</span><span class="o">.</span><span class="n">_instances</span><span class="p">[</span><span class="n">cls</span><span class="p">]</span>
</span><span class='line'>
</span><span class='line'><span class="k">class</span> <span class="nc">MyClass</span><span class="p">(</span><span class="n">BaseClass</span><span class="p">):</span>
</span><span class='line'> <span class="n">__metaclass__</span> <span class="o">=</span> <span class="n">Singleton</span>
</span><span class='line'>
</span><span class='line'><span class="n">c</span> <span class="o">=</span> <span class="n">MyClass</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
<p><strong>忧点</strong></p>
<ul>
<li><code>MyClass</code>是真的类(class)</li>
<li>魔术般地覆盖了继承的案例。</li>
<li>有目的地使用<code>__metaclass__</code>，让阅读者明确地知道这个目的。</li>
</ul>
<p><strong>缺点</strong></p>
<ul>
<li>如果有的话，就是很多程序员不熟悉元类(MetaClass)。</li>
</ul>
<h2>方法4：装饰器(Decorator)返回相同名称的类(Class)</h2>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
<span class='line-number'>7</span>
<span class='line-number'>8</span>
<span class='line-number'>9</span>
<span class='line-number'>10</span>
<span class='line-number'>11</span>
<span class='line-number'>12</span>
<span class='line-number'>13</span>
<span class='line-number'>14</span>
<span class='line-number'>15</span>
<span class='line-number'>16</span>
<span class='line-number'>17</span>
<span class='line-number'>18</span>
<span class='line-number'>19</span>
<span class='line-number'>20</span>
<span class='line-number'>21</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="k">def</span> <span class="nf">singleton</span><span class="p">(</span><span class="n">class_</span><span class="p">):</span>
</span><span class='line'> <span class="k">class</span> <span class="nc">class_w</span><span class="p">(</span><span class="n">class_</span><span class="p">):</span>
</span><span class='line'> <span class="n">_instance</span> <span class="o">=</span> <span class="bp">None</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">__new__</span><span class="p">(</span><span class="n">class_</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
</span><span class='line'> <span class="k">if</span> <span class="n">class_w</span><span class="o">.</span><span class="n">_instance</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
</span><span class='line'> <span class="n">class_w</span><span class="o">.</span><span class="n">_instance</span> <span class="o">=</span> <span class="nb">super</span><span class="p">(</span><span class="n">class_w</span><span class="p">,</span> <span class="n">class_</span><span class="p">)</span><span class="o">.</span><span class="n">__new__</span><span class="p">(</span><span class="n">class_</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</span><span class='line'> <span class="n">class_w</span><span class="o">.</span><span class="n">_instance</span><span class="o">.</span><span class="n">_sealed</span> <span class="o">=</span> <span class="bp">False</span>
</span><span class='line'> <span class="k">return</span> <span class="n">class_w</span><span class="o">.</span><span class="n">_instance</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
</span><span class='line'> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_sealed</span><span class="p">:</span>
</span><span class='line'> <span class="k">return</span>
</span><span class='line'> <span class="nb">super</span><span class="p">(</span><span class="n">class_w</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">__init__</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
</span><span class='line'> <span class="bp">self</span><span class="o">.</span><span class="n">_sealed</span> <span class="o">=</span> <span class="bp">True</span>
</span><span class='line'> <span class="n">class_w</span><span class="o">.</span><span class="n">__name__</span> <span class="o">=</span> <span class="n">class_</span><span class="o">.</span><span class="n">__name__</span>
</span><span class='line'> <span class="k">return</span> <span class="n">class_w</span>
</span><span class='line'>
</span><span class='line'><span class="nd">@singleton</span>
</span><span class='line'><span class="k">class</span> <span class="nc">MyClass</span><span class="p">(</span><span class="n">BaseClass</span><span class="p">):</span>
</span><span class='line'> <span class="k">pass</span>
</span><span class='line'>
</span><span class='line'><span class="n">c</span> <span class="o">=</span> <span class="n">MyClass</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
<p><strong>优点</strong></p>
<ul>
<li><code>MyClass</code>是真的类(class)</li>
<li>魔术般地覆盖了继承的案例。</li>
</ul>
<p><strong>缺点</strong></p>
<ul>
<li>生成一个新类有额外的开销没？每定义一个类，实际上生成了两个类来实现单体实例。通常情况下不是问题，但扩展的时候可能有麻烦。</li>
<li>对于<code>_sealed</code>属性有什么观点了？</li>
<li><code>MyClass</code>是另外一个具有同样名称的<code>MyClass</code>类的子类，是否有点怪诞？这就意味着<strong>你不能在子类的方法中通过<code>super</code>方法调用基类的相同的方法</strong>，因为这是递归调用。</li>
</ul>
<hr />
<p>上面列出了四种不同的方式实现了单体实例，分别用到了装饰器(Decorator)，元类(MetaClass)，和多继承(Multiple Inheritance)等语言特征(实际上还有很多其他实现方式)。如果程序中用不到类(class)相关的函数和方法，第一种方法就已经足够了，否则我们只能考虑方法2、3或者4。</p>
<p><strong>还有没有更简单的方法了？？？</strong></p>
<p>抛开固有的思维模式，<strong>keep it simple!</strong></p>
<p>在<a href="http://stackoverflow.com/a/6760726/1070484">stackoverflow</a>上投票最
多的答案是：</p>
<blockquote><p>Modules are imported only once, everything else is overthinking. Don’t use singletons and try not to use globals.</p></blockquote>
<p>用代码解释就是：</p>
<ul>
<li>定义一个模块，如<code>mymodule</code></li>
</ul>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
<span class='line-number'>4</span>
<span class='line-number'>5</span>
<span class='line-number'>6</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="c"># mymodule.py</span>
</span><span class='line'><span class="k">class</span> <span class="nc">Foo</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
</span><span class='line'> <span class="k">def</span> <span class="nf">somemethod</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
</span><span class='line'> <span class="k">pass</span>
</span><span class='line'>
</span><span class='line'><span class="n">some_global_variable</span> <span class="o">=</span> <span class="n">Foo</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
<ul>
<li>在其他模块中引入该实例：</li>
</ul>
<figure class='code'><figcaption><span></span></figcaption><div class="highlight"><table><tr><td class="gutter"><pre class="line-numbers"><span class='line-number'>1</span>
<span class='line-number'>2</span>
<span class='line-number'>3</span>
</pre></td><td class='code'><pre><code class='python'><span class='line'><span class="kn">from</span> <span class="nn">mymodule</span> <span class="kn">import</span> <span class="n">some_global_variable</span> <span class="k">as</span> <span class="n">foo</span>
</span><span class='line'>
</span><span class='line'><span class="n">foo</span><span class="o">.</span><span class="n">somemethod</span><span class="p">()</span>
</span></code></pre></td></tr></table></div></figure>
]]></content>
</entry>
<entry>
<title type="html"><![CDATA[在 Markdown 中嵌入 UML 文档]]></title>
<link href="http://xiaocong.github.io/blog/2013/04/22/writing-development-documentation-with-markdown/"/>
<updated>2013-04-22T13:23:00+08:00</updated>
<id>http://xiaocong.github.io/blog/2013/04/22/writing-development-documentation-with-markdown</id>
<content type="html"><![CDATA[<p><a href="http://daringfireball.net/projects/markdown/" title="Markdown">Markdown</a>是网络书写语言，特别适合程序员书写文档：</p>
<ul>
<li>全文本格式，方便进行<code>diff</code>，<code>patch</code>和版本的管理；</li>
<li>格式直观，简单易学，便于书写和阅读；</li>
<li>兼容 HTML，能方便地转换为 pdf，doc等格式；</li>
<li>支持 Linux，Windows，Mac；</li>
<li>支持内嵌代码和语法高亮；</li>
</ul>
<p>估计只是方便版本管理，就能吸引很多程序员的兴趣，特别是需要团队一起参与书写文档的时候。感兴趣的可以参考官方网站，或者以前写的一份<a href="http://xiaocong.github.io/slides/writing-documentation-with-markdown/">使用 Markdown 的 slides</a>。</p>
<p>但是毕竟<a href="http://daringfireball.net/projects/markdown/" title="Markdown">Markdown</a>只是书写语言，不是程序设计语言，如果我们需要嵌入 UML 的时候，不可避免地需要其他专业软件的支持。这里介绍几种利用网络服务，可以直接在<a href="http://daringfireball.net/projects/markdown/" title="Markdown">Markdown</a>文档中嵌入的 UML 建模图：</p>
<!--more-->
<hr />
<h2>用例图</h2>
<ul>
<li><p>角色(Actor)</p>
<p> 使用<code>[角色名]</code>表示角色。</p>
<pre><code> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]" ></p></li>
<li><p>用例(Use Case)</p>
<p> 使用<code>(用例名)</code>表示用例，<code>-</code>表示角色和用例之间的关联。</p>
<pre><code> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login),[Customer]-(Logout)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login),[Customer]-(Logout)" ></p></li>
<li><p>备注(Notes)</p>
<p> 如果用例名以<code>note:</code>开头，表明那是一个备注，可以用<code>{bg:颜色名}</code>定义备注的背景色。</p>
<pre><code> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login), [Customer]-(note: Cust can be registered or not{bg:beige})" >
</code></pre>
<p> <img src="http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login), [Customer]-(note: Cust can be registered or not{bg:beige})" ></p></li>
<li><p>角色继承(Actor Inheritance)</p>
<p> 使用符号<code>^</code>表示角色之间的继承关系。</p>
<pre><code> <img src="http://yuml.me/diagram/scruffy/usecase/[Cms Admin]^[User], [Customer]^[User], [Agent]^[User]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/scruffy/usecase/[Cms Admin]^[User], [Customer]^[User], [Agent]^[User]" ></p></li>
<li><p>扩展和包含(Extends and Includes)</p>
<p> 使用<code>></code>表示用例之间的包含关系，<code><</code>表示用例的扩展。</p>
<pre><code> <img src="http://yuml.me/diagram/scruffy/usecase/(Login)<(Register),(Login)<(Request Password Reminder),(Register)>(Confirm Registration)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/scruffy/usecase/(Login)%3C(Register),(Login)%3C(Request%20Password%20Reminder),(Register)%3E(Confirm%20Registration)" ></p></li>
<li><p>完整示例</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/usecase/(note: figure 1.2{bg:beige}), [User]-(Login),[Site Maintainer]-(Add User),(Add User)<(Add Company),[Site Maintainer]-(Upload Docs),(Upload Docs)<(Manage Folders),[User]-(Upload Docs), [User]-(Full Text Search Docs), (Full Text Search Docs)>(Preview Doc),(Full Text Search Docs)>(Download Docs), [User]-(Browse Docs), (Browse Docs)>(Preview Doc), (Download Docs), [Site Maintainer]-(Post New Event To The Web Site), [User]-(View Events)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/usecase/(note:%20figure%201.2%7Bbg:beige%7D),%20[User]-(Login),[Site%20Maintainer]-(Add%20User),(Add%20User)%3C(Add%20Company),[Site%20Maintainer]-(Upload%20Docs),(Upload%20Docs)%3C(Manage%20Folders),[User]-(Upload%20Docs),%20[User]-(Full%20Text%20Search%20Docs),%20(Full%20Text%20Search%20Docs)%3E(Preview%20Doc),(Full%20Text%20Search%20Docs)%3E(Download%20Docs),%20[User]-(Browse%20Docs),%20(Browse%20Docs)%3E(Preview%20Doc),%20(Download%20Docs),%20[Site%20Maintainer]-(Post%20New%20Event%20To%20The%20Web%20Site),%20[User]-(View%20Events)" ></p></li>
</ul>
<p><a href="http://yuml.me/">YUML</a>支持3种图示风格，分别是：</p>
<ul>
<li>plain</li>
<li>scruffy</li>
<li>boring</li>
</ul>
<p>你可以对比下列图示的不同风格：</p>
<p><img src="http://yuml.me/diagram/plain/usecase/[Customer]-(Login),[Customer]-(Logout),(login)<(Register)" >
<img src="http://yuml.me/diagram/scruffy/usecase/[Customer]-(Login),[Customer]-(Logout),(login)<(Register)" >
<img src="http://yuml.me/diagram/boring/usecase/[Customer]-(Login),[Customer]-(Logout),(login)<(Register)" ></p>
<h2>活动图</h2>
<ul>
<li><p>动作(Action)</p>
<p> 用<code>(状态名)</code>表示一个状态，其中<code>(start)</code>和<code>(end)</code>分别表示开始状态和结束状态，箭头<code>-></code>表示状态的转换。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/activity/(start)->(Boil Kettle)->(end)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/activity/(start)-%3E(Boil%20Kettle)-%3E(end)" ></p></li>
<li><p>判断和限制(Decisions and Constraints)</p>
<p> 使用<code><判断名></code>表示一个条件判断，其后跟<code>[条件]-></code>表示满足条件后状态的转换；用不同的<code>判断名</code>来标识不同的判定位置。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/activity/(start)-><a>[kettle empty]->(Fill Kettle)->(Boil Kettle),<a>[kettle full]->(Boil Kettle)->(end)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/activity/(start)-%3E%3Ca%3E[kettle%20empty]-%3E(Fill%20Kettle)-%3E(Boil%20Kettle),%3Ca%3E[kettle%20full]-%3E(Boil%20Kettle)-%3E(end)" ></p></li>
<li><p>分支合并(Fork/Join)</p>
<p> 使用<code>||</code>表示分支或者合并点。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/activity/(start)-><a>[kettle empty]->(Fill Kettle)->|b|,<a>[kettle full]->|b|->(Boil Kettle)->|c|,|b|->(Add Tea Bag)->(Add Milk)->|c|->(Pour Water)->(end),(Pour Water)->(end)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/activity/(start)-%3E%3Ca%3E[kettle%20empty]-%3E(Fill%20Kettle)-%3E%7Cb%7C,%3Ca%3E[kettle%20full]-%3E%7Cb%7C-%3E(Boil%20Kettle)-%3E%7Cc%7C,%7Cb%7C-%3E(Add%20Tea%20Bag)-%3E(Add%20Milk)-%3E%7Cc%7C-%3E(Pour%20Water)-%3E(end),(Pour%20Water)-%3E(end)" ></p></li>
<li><p>对象(Objects)</p>
<p> 符号<code>[]</code>表示一个对象。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/activity/(start)->[Water]->(Fill Kettle)->(end)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/activity/(start)-%3E[Water]-%3E(Fill%20Kettle)-%3E(end)" ></p></li>
<li><p>连接器名称(Connector Name)</p>
<p> 在<code>-></code>中加入名称，<code>-名称></code>表示命名连接器。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/activity/(start)-fill>(Fill Kettle)->(end)" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/activity/(start)-fill%3E(Fill%20Kettle)-%3E(end)" ></p></li>
</ul>
<h2>类图</h2>
<ul>
<li><p>关联(Association)</p>
<p> 类名用<code>[]</code>表示，<code>-></code>表示定向关联，<code>-</code>表明关联。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Customer]->[Billing Address]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Customer]-%3E[Billing%20Address]" ></p></li>
<li><p>基数(Cardinality)</p>
<p> <code>基数-基数></code>表明关联的基数，其中基数可以为<code>0</code>，<code>1</code>，<code>0..*</code>，<code>*</code>等任意定义的值。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Customer]1-0..*[Address]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Customer]1-0..*[Address]" ></p></li>
<li><p>定向关联(Directional Association)</p>
<p> 定向关联<code>-></code>可以定义名称：<code>-名称></code>。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Order]-billing >[Address], [Order]-shipping >[Address]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Order]-billing%20%3E[Address],%20[Order]-shipping%20%3E[Address]" ></p></li>
<li><p>颜色和UTF8字符(Splash of Colour And UTF-8)</p>
<p> 类图可以用<code>{bg:颜色名}</code>定义显示的背景颜色。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[❝Customer❞{bg:orange}]❶- ☂>[Order{bg:green}]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[%E2%9D%9DCustomer%E2%9D%9E%7Bbg:orange%7D]%E2%9D%B6-%20%E2%98%82%3E[Order%7Bbg:green%7D]" ></p></li>
<li><p>聚合(Aggregation)</p>
<p> 聚合表示比关联更强的关联关系，使用<code><>-></code>或者<code>+-></code>来表示。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Company]<>-1>[Location], [Location]+->[Point]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Company]%3C%3E-1%3E[Location],%20[Location]+-%3E[Point]" ></p></li>
<li><p>组成(Composition)</p>
<p> 组成表示比聚合更强的关联关系，使用<code>++-></code>来表示。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Company]++-1>[Location]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Company]++-1%3E[Location]" ></p></li>
<li><p>备注(Notes)</p>
<p> 使用<code>[note:注解内容]</code>表示备注，同样备注可以自定义颜色<code>{bg:颜色名}</code>。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Customer]<>1->*[Order], [Customer]-[note: Aggregate Root{bg:cornsilk}]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Customer]%3C%3E1-%3E*[Order],%20[Customer]-[note:%20Aggregate%20Root%7Bbg:cornsilk%7D]" ></p></li>
<li><p>继承(Inheritance)</p>
<p> 使用<code>^-</code>表示类的继承，右边的类是子类。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[Wages]^-[Salaried], [Wages]^-[Contractor]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[Wages]%5E-[Salaried],%20[Wages]%5E-[Contractor]" ></p></li>
<li><p>接口继承(Interface Inheritance)</p>
<p> 接口继承用<code>^-.-</code>来表示。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[<<ITask>>]^-.-[NightlyBillingTask]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[%3C%3CITask%3E%3E]%5E-.-[NightlyBillingTask]" ></p></li>
<li><p>依赖(Dependencies)</p>
<p> 类的依赖用<code>-.-></code>来表示，依赖是最弱的关联关系，一般用来表示类方法的参数或者实现用到了依赖类。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[HttpContext]uses -.->[Response]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[HttpContext]uses%20-.-%3E[Response]" ></p></li>
<li><p>接口(Interface)</p>
<p> 和类名相比，接口的名称一般包含在<code><<>></code>中。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[<<IDisposable>>;Session]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[%3C%3CIDisposable%3E%3E;Session]" ></p></li>
<li><p>类定义(Class with Details)</p>
<p> 可以在类符号<code>[]</code>中定义类的所有成员。使用<code>|</code>表示类名与类成员变量和成员函数的分割符，不同的成员之间用<code>;</code>隔开，使用<code>+</code>，<code>-</code>分别表示公开和私有成员。</p>
<pre><code> <img src="http://yuml.me/diagram/nofunky/class/[User|+Forename+;Surname;+HashedPassword;-Salt|+Login();+Logout()]" >
</code></pre>
<p> <img src="http://yuml.me/diagram/nofunky/class/[User%7C+Forename+;Surname;+HashedPassword;-Salt%7C+Login();+Logout()]" ></p></li>