PYTHON 爬虫笔记六:PyQuery库基础用法
2024-10-19 14:31:53
知识点一：PyQuery库详解及其基本使用
初始化
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="boid">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('li'))#选择器实际上就是CSS选择器，即：选id就加“#”，选class前面加“.”<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0 active"><a href="link3.html"><span class="boid">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>获得的结果
URL初始化
from pyquery import PyQuery as pq
doc1 = pq(url = "http://www.baidu.com") print(doc1("head"))<head><meta http-equiv="content-type" content="text/html;charset=utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=Edge"/><meta content="always" name="referrer"/><link rel="stylesheet" type="text/css" href="http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css"/><title>ç¾åº¦ä¸ä¸ï¼ä½ å°±ç¥é</title></head>
获得的结果
文件初始化
from pyquery import PyQuery as pq
doc2 = pq(filename = "demo.html")#自己下载一个HTML文件 print(doc2('li'))
基本CSS选择器
实例
tml = '''
<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="boid">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"))#注意空格，空格代表嵌套关系<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0 active"><a href="link3.html"><span class="boid">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>获得的结果
查询元素
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="boid">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")#首先选中url标签 print(type(items))
print(items) lis = items.find('li')#实际上也是一个CSS选择器，将里面所有的li标签都打印出来；只要在它里面的标签都可以找到
print(type(lis))
print(lis) #查找直接子元素
lis2 = items.children()
print(type(lis2))
print(lis2) lis3 = items.children('.active')
print(lis3)<class 'pyquery.pyquery.PyQuery'>
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0 active"><a href="link3.html"><span class="boid">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> <class 'pyquery.pyquery.PyQuery'>
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0 active"><a href="link3.html"><span class="boid">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> <class 'pyquery.pyquery.PyQuery'>
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0 active"><a href="link3.html"><span class="boid">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> <li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li>
<li class="item-1 active"><a href="link4.html">fourth item</a></li>获得的结果
父元素
#父元素
html = '''
<div id="container">
<ul class="list">
<li class="item-0">first item</li>
<li class="item-1"><a href="link2.html">second item</a></li>
<li class="item-0 active"><a href="link3.html"><span class="boid">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")#首先选中url标签
#每个标签外面肯定只能套一个父元素
container = items.parent() print(type(container))
print(container)<class 'pyquery.pyquery.PyQuery'>
<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="boid">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>获得的结果
另一种方法：
html = '''
<div class="wrap">
<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="boid">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>
</div>
''' from pyquery import PyQuery as pq
doc = pq(html)
items = doc(".list")#首先选中url标签
#将所有祖先节点返回
parents = items.parents() print(parents)
print(type(parents))#打印出两个div另一种方法
<html><body><div class="wrap">
<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><li class="item-0 active"><a href="link3.html"><span class="boid">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>
</div>
</body></html><body><div class="wrap">
<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><li class="item-0 active"><a href="link3.html"><span class="boid">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>
</div>
</body><div class="wrap">
<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><li class="item-0 active"><a href="link3.html"><span class="boid">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>
</div>
<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><li class="item-0 active"><a href="link3.html"><span class="boid">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'>--->获得的结果
html = '''
<div class="wrap">
<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="boid">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>
</div>
''' from pyquery import PyQuery as pq
doc = pq(html)
items = doc(".list")#首先选中url标签 #在其中进行搜索
parents1 = items.parents(".wrap") print(parents1)#通过筛选，只剩下一个div获取单一内容
<div class="wrap">
<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><li class="item-0 active"><a href="link3.html"><span class="boid">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>
</div>--->获得的结果
兄弟元素
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html)
li = doc('.list .item-0.active')#首先选class=“.list”，空格即使选择list里面的标签，再选class=“item-0”，并列active（实际就是一个整体）
print(li)
print(li.siblings())#获取所有的兄弟元素<li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li> <li class="item-1"><a href="link2.html">second item</a><>/li
</li><li class="item-0">first item</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>获得的结果
另一种方式：
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) li = doc('.list .item-0.active')#首先选class=“.list”，空格即使选择list里面的标签，再选class=“item-0”，并列active（实际就是一个整体）
#在向其中筛选
print(li.siblings('.active'))另一种方式
<li class="item-1 active"><a href="link4.html">fourth item</a></li>
--->获得的结果
遍历
单个元素
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) li = doc(".item-0.active")
print(li)<li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li>
获得的方法
另一种方式
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) lis = doc('li').items()#多个元素，进行遍历，生成一个产生器 print(type(lis))
for li in lis:
print(li)另一种方式
<class 'generator'>
<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="boid">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>--->获得的结果
获取信息
获取属性
html = '''
<div class="wrap">
<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="boid">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>
</div>
''' from pyquery import PyQuery as pq
doc = pq(html)
a = doc(".item-0.active a")#选择class同时为item-0和active，在选择class里面的啊标签，中间注意空格
print(a)
print(a.attr("href"))
print(a.attr.href)#结果同上<a href="link3.html"><span class="boid">third item</span></a>
link3.html
link3.html获得的结果
获取文本
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html)
a = doc(".item-0.active a") print(a)
print(a.text())#将上面的选中的class中包围的文字<a href="link3.html"><span class="boid">third item</span></a>
third item获得的结果
获取HTML
html = '''
<div class="wrap">
<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="boid">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>
</div>
''' from pyquery import PyQuery as pq
doc = pq(html)
a = doc(".item-0.active") print(a)
print(a.html())<li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li> <a href="link3.html"><span class="boid">third item</span></a>
获得的结果
DOM操作
address,removeClass
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) li = doc(".item-0.active")
print(li) li.removeClass("active")#移除active
print(li) li.addClass("active")#增加active
print(li)<li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li> <li class="item-0"><a href="link3.html"><span class="boid">third item</span></a></li> <li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li>获得的结果
attr,css
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) li = doc(".item-0.active")
print(li) li.attr("name","link")#若存在，就会覆盖
print(li) li.css("font-size","14px")#增加style属性
print(li)<li class="item-0 active"><a href="link3.html"><span class="boid">third item</span></a></li> <li class="item-0 active" name="link"><a href="link3.html"><span class="boid">third item</span></a></li> <li class="item-0 active" name="link" style="font-size: 14px"><a href="link3.html"><span class="boid">third item</span></a></li>
获得的结果
remove
html1 = '''
<div class="wrap">
Hello,World
<p>This is a paragraph.</p>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html1) wrap = doc(".wrap")
print(wrap.text()) wrap.find('p').remove() print(wrap.text())Hello,World
This is a paragraph.
Hello,World获得的结果
其他DOM操作
- 其他DOM方法： http://pythonhosted.org/pyquery/
伪类选择器
html = '''
<div class="wrap">
<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="boid">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>
</div>
'''
from pyquery import PyQuery as pq
doc = pq(html) li = doc("li:first-child")#第一个
print(li) li1 = doc('li:last-child')#最后一个
print(li1) li2 = doc('li:nth-child(2)')#指定缩写顺序，第二个
print(li2) li3 = doc("li:gt(2)")#大于2的（从0开始）
print(li3) li4 = doc("li:nth-child(2n)")#偶数
print(li4) li5 = doc("li:contains(second)")#内容包含second
print(li5)<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="link2.html">second item</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> <li class="item-1"><a href="link2.html">second item</a></li>
<li class="item-1 active"><a href="link4.html">fourth item</a></li> <li class="item-1"><a href="link2.html">second item</a></li>获得的结果
更多CSS选择器可以查看：http://www.w3school.com.cn/css/index.asp
官方文档
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