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open()内建函数，第一个参数是文件绝对路径，第二个是对文件操作的权限
r以读方式打开文件，可读取文件信息。
w以写方式打开文件，可向文件写入信息。如文件存在，则清空该文件，再写入新内容
a以追加模式打开文件（即一打开文件，文件指针自动移到文件末尾），如果文件不存在则创建
r+以读写方式打开">
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open()内建函数，第一个参数是文件绝对路径，第二个是对文件操作的权限
r以读方式打开文件，可读取文件信息。
w以写方式打开文件，可向文件写入信息。如文件存在，则清空该文件，再写入新内容
a以追加模式打开文件（即一打开文件，文件指针自动移到文件末尾），如果文件不存在则创建
r+以读写方式打开">
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open()内建函数，第一个参数是文件绝对路径，第二个是对文件操作的权限
r以读方式打开文件，可读取文件信息。
w以写方式打开文件，可向文件写入信息。如文件存在，则清空该文件，再写入新内容
a以追加模式打开文件（即一打开文件，文件指针自动移到文件末尾），如果文件不存在则创建
r+以读写方式打开">
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                python 文件操作
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        <span itemprop="articleBody"><h3 id="正常打开文件读取"><a href="#正常打开文件读取" class="headerlink" title="正常打开文件读取"></a>正常打开文件读取</h3><p>f = open(‘/root/Desktop/test/chen.txt’,’rt’)</p>
<p>open()内建函数，第一个参数是文件绝对路径，第二个是对文件操作的权限</p>
<p>r<br>以读方式打开文件，可读取文件信息。</p>
<p>w<br>以写方式打开文件，可向文件写入信息。如文件存在，则清空该文件，再写入新内容</p>
<p>a<br>以追加模式打开文件（即一打开文件，文件指针自动移到文件末尾），如果文件不存在则创建</p>
<p>r+<br>以读写方式打开文件，可对文件进行读和写操作。</p>
<p>w+<br>消除文件内容，然后以读写方式打开文件。</p>
<p>a+<br>以读写方式打开文件，并把文件指针移到文件尾。</p>
<p>b<br>以二进制模式打开文件，而不是以文本模式。该模式只对Windows或Dos有效，类Unix的文件是用二进制模式进行操作的。</p>
<h3 id="with"><a href="#with" class="headerlink" title="with"></a>with</h3><pre><code>with open(&apos;somefile.txt&apos;, &apos;rt&apos;) as f:
    data = f.read()
</code></pre><p>为了写入一个文本文件，使用带有 wt 模式的 open() 函数， 如果之前文件内容存在则清除并覆盖掉。如下所示:</p>
<pre><code># Write chunks of text data
with open(&apos;somefile.txt&apos;, &apos;wt&apos;) as f:
    f.write(text1)
    f.write(text2)
# Redirected print statement
with open(&apos;somefile.txt&apos;, &apos;wt&apos;) as f:
    print(line1, file=f)
    print(line2, file=f)
</code></pre><p>如果是在已存在文件中添加内容，使用模式为 at 的 open() 函数</p>
<p>文件的读写操作默认使用系统编码，可以通过调用 sys.getdefaultencoding() 来得到。 在大多数机器上面都是utf-8编码。如果你已经知道你要读写的文本是其他编码方式， 那么可以通过传递一个可选的 encoding 参数给open()函数。如下所示：</p>
<pre><code>with open(&apos;somefile.txt&apos;, &apos;rt&apos;, encoding=&apos;latin-1&apos;) as f:
</code></pre><p>Python支持非常多的文本编码。几个常见的编码是ascii, latin-1, utf-8和utf-16。 在web应用程序中通常都使用的是UTF-8。 ascii对应从U+0000到U+007F范围内的7位字符。 latin-1是字节0-255到U+0000至U+00FF范围内Unicode字符的直接映射。 当读取一个未知编码的文本时使用latin-1编码永远不会产生解码错误。 使用latin-1编码读取一个文件的时候也许不能产生完全正确的文本解码数据， 但是它也能从中提取出足够多的有用数据。同时，如果你之后将数据回写回去，原先的数据还是会保留的。</p>
<h3 id="file"><a href="#file" class="headerlink" title="file"></a>file</h3><pre><code>print file(&apos;/root/Desktop/test/chen.txt&apos;, &apos;rt&apos;).read()
</code></pre><h3 id="file与open-区别"><a href="#file与open-区别" class="headerlink" title="file与open 区别"></a>file与open 区别</h3><p>python3没有file了，基本这俩一样</p>
<h3 id="什么是IO？"><a href="#什么是IO？" class="headerlink" title="什么是IO？"></a>什么是IO？</h3><p>i就是input输入,O就是output输出,一起就是基本输入输出设备<br>I/O也就是输入输出地址。每个设备都会有一个专用的I/O地址，用来处理自己的输入输出信息。I/O地址绝对不能重复，如果两个设备的I/O地址有冲突，系统硬件就不能正常工作。以Windows XP操作系统为例，查看一个设备所占用的I/O地址的方法是：在系统桌面中选择“我的电脑”，单击鼠标右键，选择“属性”，在弹出的“系统属性”对话框中选择“硬件”，单击“设备管理器”按钮，弹出一个“设备管理器”窗口，在设备列表中双击要查看的I/O地址设备类型，然后双击具体的设备名称，在弹出对话框的“资源”选项卡中就可以看到该设备所占用的I/O地址了。在“资源设置”区域，可以看到显卡占用的I/O地址。 </p>
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      element.on('mousewheel DOMMouseScroll', function (event) {
          var oe = event.originalEvent;
          var delta = oe.wheelDelta || -oe.detail;
          this.scrollTop += ( delta < 0 ? 1 : -1 ) * 30;
          event.preventDefault();
          toggleTOCOverflowIndicators();
    function tocOverflowIndicator (indicator, action) {
      var $indicator = $(indicator);
      var opacity = action === 'show' ? 1 : 0;
      $indicator.velocity ?
        $indicator.velocity('stop').velocity({
          opacity: opacity
        }, { duration: 100 }) :
        $indicator.stop().animate({
          opacity: opacity
        }, 100);
<script type="text/javascript" id="sidebar.nav">
  $(document).ready(function () {
    var html = $('html');
    var TAB_ANIMATE_DURATION = 200;
    var hasVelocity = $.isFunction(html.velocity);
    $('.sidebar-nav li').on('click', function () {
      var item = $(this);
      var activeTabClassName = 'sidebar-nav-active';
      var activePanelClassName = 'sidebar-panel-active';
      if (item.hasClass(activeTabClassName)) {
        return;
      var currentTarget = $('.' + activePanelClassName);
      var target = $('.' + item.data('target'));
      hasVelocity ?
        currentTarget.velocity('transition.slideUpOut', TAB_ANIMATE_DURATION, function () {
          target
            .velocity('stop')
            .velocity('transition.slideDownIn', TAB_ANIMATE_DURATION)
            .addClass(activePanelClassName);
        }) :
        currentTarget.animate({ opacity: 0 }, TAB_ANIMATE_DURATION, function () {
          currentTarget.hide();
          target
            .stop()
            .css({'opacity': 0, 'display': 'block'})
            .animate({ opacity: 1 }, TAB_ANIMATE_DURATION, function () {
              currentTarget.removeClass(activePanelClassName);
              target.addClass(activePanelClassName);
        });
      item.siblings().removeClass(activeTabClassName);
      item.addClass(activeTabClassName);
    $('.post-toc a').on('click', function (e) {
      e.preventDefault();
      var targetSelector = escapeSelector(this.getAttribute('href'));
      var offset = $(targetSelector).offset().top;
      hasVelocity ?
        html.velocity('stop').velocity('scroll', {
          offset: offset  + 'px',
          mobileHA: false
        }) :
        $('html, body').stop().animate({
          scrollTop: offset
        }, 500);
    // Expand sidebar on post detail page by default, when post has a toc.
    motionMiddleWares.sidebar = function () {
      var $tocContent = $('.post-toc-content');
      if (CONFIG.sidebar === 'post') {
        if ($tocContent.length > 0 && $tocContent.html().trim().length > 0) {
          displaySidebar();
  <script type="text/javascript" src="/js/bootstrap.js"></script>
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