在讲python include标签使用之前，我们新建一个include_demo项目
项目新建好了，再在templates文件下新建一个index.html文件，代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
*{margin:0;padding:0;}
ul{list-style: none;}
a{text-decoration: none;
color: #ffffff;}
nav,footer,.main{width:1000px; height:40px; margin:0 auto;}
ul{width: 1000px; height:40px; line-height: 40px;
background-color:#000000;}
li{width:120px; height:40px; line-height:40px; text-align: center;
float:left;}
.main{clear:both; line-height:40px; background-color:pink;}
footer{height:40px; background-color: green;}
</style>
</head>
<body>
<nav>
<ul>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >首页</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >关于我们</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >产品中心</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新闻中心</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >服务宗旨</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >联系我们</a></li>
</ul>
</nav>
<div class="main">
网站首页主体部分
</div>
<footer>
网站首页footer部分
</footer>
</body>
</html>然后在include_demo.py页面渲染一下index模板文件，代码如下：
from flask import Flask,render_template
app = Flask(__name__)
@app.route('/')
def hello_world():
return render_template("index.html")
if __name__ == '__main__':
app.run(debug=True)运行include_demo.py文件，运行结果如下：
在这里主要是为了方便讲解include标签，所有没太注重前端页面部分。
通过上面index.html文件就能发现，我将公共和私有代码部分都在一块，假设网站有几十个页面，我将所有公共代码和私有代码
都放一块，如果有一天要修改某个公共代码块，哪就得修改几十个页面，那将是件非常麻烦的事。为了方便管理项目，我们将页面公共、私有代码部分抽取出来。
我们新建一个header.html文件，把css样式及nav标签内容复制到header.html页面中。
代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
*{margin:0;padding:0;}
ul{list-style: none;}
a{text-decoration: none;
color: #ffffff;}
nav,footer,.main{width:1000px; height:40px; margin:0 auto;}
ul{width: 1000px; height:40px; line-height: 40px;
background-color:#000000;}
li{width:120px; height:40px; line-height:40px; text-align: center;
float:left;}
.main{clear:both; line-height:40px; background-color:pink;}
footer{height:40px; background-color: green;}
</style>
</head>
<body>
<nav>
<ul>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >首页</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >关于我们</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >产品中心</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >新闻中心</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >服务宗旨</a></li>
<li><a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >联系我们</a></li>
</ul>
</nav>
</body>
</html>然后新建一个footer.html文件，把footer标签中的内容复制到该文件中。
代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<footer>
网站首页footer部分
</footer>
</footer>
</body>
</html>我们在运行主app文件，结果如下：
(＾－＾)，为啥没有居中，背景色也不见了？？因为我们没有把样式引入进来（嗯，页面太丑了，没法看了，赶紧关了！！）
OK！我们将公共代码抽取出来后。记得在index.html文件中用include标签导入header、footer代码块，代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
{% include "header.html" %}
<div class="main">
网站首页主体部分
</div>
{% include "footer.html" %}
</body>
</html>再运行主app文件，结果如下：
嗯，结果是不是和之前一样，对吧！
通过上面例子，相信大部分小伙伴都明白了include标签的作用及用法。总之一句话，include标签的作用就相当于把抽取的代码复制到当前页面中。
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
