PyQuery
什么是PyQuery
PyQuery是强大又灵活的网页解析库。如果熟悉jQuery的语法，那么PyQuery就是你的绝佳选择
安装PyQuery
pip3 install PyQuery
用法讲解
初始化
字符串初始化常用在得到网页源代码，然后进行解析。
html = """
<div>
<ul>
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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('li'))#这里传入CSS选择器，标签选择器，结果返回所有li
URL初始化
from pyquery import PyQuery as pq
doc = pq(url='http://www.baidu.com')#使用url初始化
print(doc('head'))#返回html中的head
文件初始化
from qyquery import PyQuery as pq
doc = pq(filename='myhtml.html')
print(doc('li'))
基本的CSS选择器
html = """
<div id="container">
<ul>
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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 .active a'))#查找id=container 下的类名为active的 下的所有a标签，只要有层级嵌套关系，不是直接父子关系。
查找元素
子元素，查找元素下的子元素
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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')
print(type(items))
print(items)
lis = items.find('li')#想jQuery一样，可以用find筛选所有子元素，无论层级
print(type(lis))
print(lis)
返回结果:返回值是<class 'pyquery.pyquery.PyQuery'>类型
<class 'pyquery.pyquery.PyQuery'>
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></a></li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
</ul>
<class 'pyquery.pyquery.PyQuery'>
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></a></li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
查找直接子元素
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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('.item-0')#可能返回多个
print(items.children())#返回直接子元素
返回值：
<a href="lin3.html"><span class="bold">third item</span></a><a href="link5.html">fifth item</a>
这里返回了2条class="item-0"的li的直接子元素
父元素
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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')
container = items.parent()
print(type(container))
print(container)#返回整个class=list的父节点--div的内容
parents()--返回所有的祖先节点。
兄弟节点
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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('.active')
print(items.siblings())#返回class=active的所有兄弟节点
print(items.siblings('.item-1'))#兄弟节点+CSS选择器
*返回结果:
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0">first item</li>
<li class="item-0"><a href="link5.html">fifth item</a></li>
<li class="item-1"><a href="link.html">second item</a></li>
遍历
- 单个元素-返回的是单个元素那么就不谈遍历了，返回的是PyQuery对象
- 多个元素，如果返回的是多个元素就用.items()，那么返回的实际上是一个生成器，可以用for循环遍历
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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('.active')
lis = items.siblings().items()
print(type(lis))
for item in lis:#遍历所有兄弟节点
print(item)
获取信息
- 获取属性
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
a = doc('.item-0.active a')
print(a)
print(a.attr('href'))#返回属性为href的值
print(a.attr.href)#同上
返回结果：
<a href="lin3.html"><span class="bold">third item</span></a>
lin3.html
lin3.html
- 获取文本
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
a = doc('.item-0.active a')
print(a)
print(a.text())#返回a标签中的内容
返回结果：
<a href="lin3.html"><span class="bold">third item</span></a>
third item
- 获取HTML
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
a = doc('.item-0.active a')
print(a)
print(a.html())#返回整个a标签的html代码
返回结果:
<a href="lin3.html"><span class="bold">third item</span></a>
<span class="bold">third item</span>
DOM操作
- addClass、removeClass
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
li = doc('.item-0.active')
print(li)
li.removeClass('active')#删除这个li的类名active
print(li)
li.addClass('active')#又加上active类名
print(li)
输出结果
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></a></li>
<li class="item-0"><a href="lin3.html"><span class="bold">third item</span></a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></a></li>
- 添加或修改attr、css
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
li = doc('.item-0.active')
print(li)
li.attr('name','mylink')#因为没有name属性，所以实际上添加name属性，值为mylink
print(li)
li.css('font-size','20px')#添加行内style
print(li)
- remove
html = """
<div class="wrap">
hello,lll
<p>This is test</p>
</div>
"""
from pyquery import PyQuery as pq
doc = pq(html)
wrap = doc('.wrap')
print(wrap.text())
wrap.find('p').remove()#删除p标签
print(wrap.text())
伪类选择器
html = """
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link.html">second item</a></li>
<li class="item-0 active"><a href="lin3.html"><span class="bold">third item</span></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)
li = doc('li:first-child')#html标签下第一个li
print(li)
li = doc('li:last-child')#html标签下最后一个li
print(li)
li = doc('li:nth-child(2)')#html标签下第二个li
print(li)
li = doc('li:gt(2)')#html标签下大于2的所有li
print(li)
li = doc('li:nth-child(2n)')#html标签下偶数的li
print(li)
li = doc('li:contains(second)')#html标签下li中的内容包含second的li
print(li)
