PyQuery库也是一个很是强大又灵活的网页解析库，若是你有前端开发经验的，都应该接触过jQuery,那么PyQuery就是你很是绝佳的选择，PyQuery 是 Python 仿照 jQuery 的严格实现。语法与 jQuery 几乎彻底相同，因此不用再去费心去记一些奇怪的方法了。
官网地址：http://pyquery.readthedocs.io/en/latest/
jQuery参考文档： http://jquery.cuishifeng.cn/css
一、字符串的初始化html
from pyquery import PyQuery as pq
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>'''
doc = pq(html)
print(doc)
print(type(doc))
print(doc('li'))
<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>
<class 'pyquery.pyquery.PyQuery'>
<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>
二、打开html文件前端
注意路劲问题java
from pyquery import PyQuery as pq
doc = pq(filename='index.html')
print(doc)
print(doc('head'))
<title>Title</title>
</head>
<body>
<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>'''
</body>
</html>
<head>
<meta charset="UTF-8"/>
<title>Title</title>
</head>
三、打开某个网站python
doc = pq('https://www.baidu.com')
# doc1 = pq(url='https://www.baidu.com')
print(doc)
print(doc('head'))
四、基于CSS选择器查找jquery
from pyquery import PyQuery as pq
html = '''<div>
<ul id = 'haha'>
<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>'''
doc = pq(html)
print(doc)
#id等于haha下面的class等于item-0下的a标签下的span标签（注意层级关系以空格隔开）
print(doc('#haha .item-0 a span'))
<div>
<ul id="haha">
<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>
<span class="bold">third item</span>
五、能够经过已经查找的标签，查找这个标签下的子标签或者父标签，而不用从头开始查找。python爬虫
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
item = doc('div ul')
print(item)
#咱们能够经过已经查找到的标签，再此查找这个标签下面的标签
print(item.parent())
print(item.children())
<ul id="haha">
<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 class="‘content’">
<ul id="haha">
<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>
<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>
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
item = doc('div ul')
print(item)
#注意这里查找ul标签的全部子标签，也就是li标签，下面是查找class属性的标签，若是你把class换成href确定不行，它指的只是儿子并非子子孙孙
print(item.children('[class]'))
六、获取属性值ide
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
#注意class=item-0 active是一个class的属性，可是在pyquery里面要是中间也是空格隔开的话，
#就变成了item-0下的active标签下的a标签了，因此这里空格必须改为点
item = doc(".item-0.active a")
print(type(item))
print(item)
#获取属性值的两种方法
print(item.attr.href)
print(item.attr('href'))
<class 'pyquery.pyquery.PyQuery'> <a href="link3.html"><span class="bold">third item</span></a> link3.html link3.html
七、获取标签的内容post
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
a = doc("a").text()
print(a)
#结果颇有趣，他是找到全部标签的值，而后给连到一块儿打出来，就像一段话 second item third item fourth item fifth item
八、Dom操做
一、属性的增长删除操做
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
li = doc('.item-0.active')
print(li)
#删除classactive
print(li.removeClass('active'))
#增长class属性haha
print(li.addClass('haha'))
<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-0"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-0 haha"><a href="link3.html"><span class="bold">third item</span></a></li>
二、attrs和css
注意：下列操做有则改之，无则加之。
from pyquery import PyQuery as pq
html = '''<div class=‘content’>
<ul id = 'haha'>
<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>'''
doc = pq(html)
li = doc('.item-0.active')
print(li)
print(li.attr('id','id_test'))
print(li.css('font-size','20px'))
<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-0 active" id="id_test"><a href="link3.html"><span class="bold">third item</span></a></li>
<li class="item-0 active" id="id_test" style="font-size: 20px"><a href="link3.html"><span class="bold">third item</span></a></li>
三、删除某个标签，在爬去过程当中咱们一般爬去一下标签或者内容下来的时候总会有些不想要的标签，这个时候咱们能够用下面的相似方法删除这个标签。
from pyquery import PyQuery as pq
html = '''<div class='content'>
<ul id = 'haha'>
<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>'''
doc = pq(html)
data = doc('.content')
print(data.text())
#删除全部a标签
data.find('a').remove()
#再次打印
print(data.text())
first item second item third item fourth item fifth item first item