1 PyQuery说明:
- PyQuery是python中一个强大而又灵活的网页解析库,如果你觉得正则写起来太麻烦,又觉得BeautifulSoup语法太难记,如果你熟悉jQuery的语法那么,PyQuery就是你绝佳的选择。
安装
pip3 install pyquery
2 初始化
介绍三种初始化PyQuery的方法。
1.字符串初始化
html = '''
<div>
<ul>
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a></li>
<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-1 active"><a href="link4.html">fourth item</a></li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
</ul>
</div>
'''
from pyquery import PyQuery as pq # 习惯写法,用字母pq来代替PyQuery类
doc = pq(html) # 声明PyQuery对象doc,传入html这个参数(字符串)
print(doc('li')) # 用css选择器来实现,如果要选id前面加#,如果选class,前面加.,如果选标签名,什么也不加
2. URL初始化
from pyquery import PyQuery as pq
doc=pq(url='http://www.baidu.com')#直接请求传入的url
print(doc('head'))
选择出了head标签
3.文件初始化
demo.html为本地文件
from pyquery import PyQuery as pq
doc=pq(filename='demo.html')#指定文件名,该文件在运行目录下
print(doc('head'))
3 基本CSS选择器
html = '''
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a></li>
<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-1 active"><a href="link4.html">fourth item</a></li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
</ul>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html)
print(doc('#container .list li'))
# 会查找id为container class为list,标签为li的对象,只是层级关系,后者并非一定是前者的子对象
# 注意用空格隔开
4 查找元素
查找子元素
html = '''
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a></li>
<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-1 active"><a href="link4.html">fourth item</a></li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
</ul>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html)
items = doc('.list