爬虫之PyQuery库的使用（八）
作者：互联网
PyQuery 概念
字符串初始化
html='''
<div>
<ul>
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
print(doc("li"))
url初始化
from pyquery import PyQuery as pq
doc=pq(url="http://www.baidu.com")
print(doc("head"))
文件初始化
from pyquery import PyQuery as pq
doc=pq(filename='demo.html')#这里的demo.html是已经保存好的html文件
print(doc("li"))
#代表id .代表class
html='''
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
print(doc('#container .list li'))#表示id为container的节点，选择其内部的class为list的节点内部的所有li节点，然后打印输出
查子元素
html='''
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
items=doc(".list")
print(type(items))#<class 'pyquery.pyquery.PyQuery'>
print(items)
lis=items.find('li')# 查找ul下面的li元素
print(type(lis))
print(lis)
查找父元素
html='''
<div class="warp">
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
items=doc(".list")
print(type(items.parent()))
print(items.parent())# 把直接父节点也打印出来
print(items.parents())# 把外层的所有节点 分别 都给打印处出来；返回所有的祖先节点
print(items.parents(".warp")) # 将指定的曾祖父打印处理，就不会像parents一样打印多种情况
html='''
<div class="warp">
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
li=doc(".list .item-0.active")
print(li.siblings())
print("**************")
print(li.siblings(".active"))
单个元素
html='''
<div class="warp">
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
li=doc(".list .item-0.active")
print(li)
# 打印结果：
#<li class="item-0 active"><a href="link3.html"><span class="bold">third item</span></a></li>
多个元素
html='''
<div class="warp">
<div id="container">
<ul class="list">
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
li=doc("li").items()# 就会生成一个迭代器 <class 'generator'>
print(type(li))
for i in li:
print(i)
获取属性
doc=pq(html)
a=doc(".item-0.active a")
print(a)
print(a.attr("href"))
print(a.attr.href) #与前面的等价
获取文本
doc=pq(html)
a=doc(".item-0.active a")
print(a)
print(a.text())
print(a.text('heelo'))#为其中添加text属性的值
获取html
doc=pq(html)
li=doc(".item-0.active")
print(li)
print(li.html('<span>changed item</span>'))#为其中添加html属性的值
doc=pq(html)
li=doc(".item-0.active")
print(li)
li.removeClass('active')#移除节点中的active
print(li)
li.addClass('active')#添加节点中的active
print(li)
# 打印结果：
#<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 active"><a href="link3.html"><span class="bold">third item</span></a></li>
参考文档:
链接: 参考文档:.
修改和增加 css，attr属性
from pyquery import PyQuery as pq
doc=pq(html)
li=doc(".item-0.active")
li.attr('name','link')# 如果属性中有name了，就会用link覆盖原来的值
print(li)
li.css('font-size','14px')
print(li)
#打印结果：
#<li class="item-0 active" name="link"><a href="link3.html"><span class="bold">third item</span></a></li>
#<li class="item-0 active" name="link" style="font-size: 14px"><a href="link3.html"><span class="bold">third item</span></a></li>
remove
html='''
<div class="wrap">
Hello,World
<p>This is a paragraph</p>
</div>
'''
from pyquery import PyQuery as pq
doc=pq(html)
wrap=doc(".wrap")
print(wrap.text())
wrap.find('p').remove()
print(wrap.text())
打印结果：
Hello,World
This is a paragraph
Hello,World
伪类选择器
html='''
<div>
<ul>
<li class="item-0">frist 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</a></li>
'''
from pyquery import PyQuery as pq
doc=pq(html)
li=doc('li:first-child')
print(li)
print("---------1-------")
li=doc('li:last-child')
print(li)
print("---------2-------")
li=doc('li:nth-child(2)')
print(li)
print("----------3------")
li=doc('li:gt(2)')#大于2编号以后的内容
print(li)
print("----------4------")
li=doc('li:contains(second)')#获取包含second的
print(li)
print("----------------")
#---------1-------
#<li class="item-1 active"><a href="link4.html">fourth</a></li>
#---------2-------
#<li class="item-1"><a href="link2.html">second item</a></li>
#----------3------
#<li class="item-1 active"><a href="link4.html">fourth</a></li>
#----------4------
#<li class="item-1"><a href="link2.html">second item</a></li>
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标签：pq,PyQuery,doc,爬虫,li,item,html,使用,print 来源： https://blog.51cto.com/u_15270205/2908806