1.xpath
1.1 Use xpath
Google installs the xpath plug-in in advance, press ctrl shift x and a small black box will appear
-
Install lxml library
pip install lxml ‐i https://pypi.douban.com/simple
Import lxml.etree
from lxml import etree
etree.parse() parses local files
html_tree = etree.parse('XX.html')
etree.HTML() Server response file
html_tree = etree.HTML(response.read().decode('utf‐8')
.html_tree.xpath(xpath path)
- Find all descendant nodes , regardless of hierarchical relationship
- Find direct child nodes
//div[@id] //div[@id="maincontent"]3.Attribute query
//@class4. Fuzzy query
//div[contains(@id, "he")] //div[starts‐with(@id, "he")]5. Content query
//div/h2/text()6. Logical operation
//div[@id="head" and @class="s_down"] //title | //price1.3 Example
xpath .html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"/> <title>Title</title> </head> <body> <ul> <li id="l1" class="class1">北京</li> <li id="l2" class="class2">上海</li> <li id="d1">广州</li> <li>深圳</li> </ul> </body> </html>
from lxml import etree # xpath解析 # 本地文件: etree.parse # 服务器相应的数据 response.read().decode('utf-8') etree.HTML() tree = etree.parse('xpath.html') # 查找url下边的li li_list = tree.xpath('//body/ul/li') print(len(li_list)) # 4 # 获取标签中的内容 li_list = tree.xpath('//body/ul/li/text()') print(li_list) # ['北京', '上海', '广州', '深圳'] # 获取带id属性的li li_list = tree.xpath('//ul/li[@id]') print(len(li_list)) # 3 # 获取id为l1的标签内容 li_list = tree.xpath('//ul/li[@id="l1"]/text()') print(li_list) # ['北京'] # 获取id为l1的class属性值 c1 = tree.xpath('//ul/li[@id="l1"]/@class') print(c1) # ['class1'] # 获取id中包含l的标签 li_list = tree.xpath('//ul/li[contains(@id, "l")]/text()') print(li_list) # ['北京', '上海'] # 获取id以d开头的标签 li_list = tree.xpath('//ul/li[starts-with(@id,"d")]/text()') print(li_list) # ['广州'] # 获取id为l2并且class为class2的标签 li_list = tree.xpath('//ul/li[@id="l2" and @class="class2"]/text()') print(li_list) # ['上海'] # 获取id为l2或id为d1的标签 li_list = tree.xpath('//ul/li[@id="l2"]/text() | //ul/li[@id="d1"]/text()') print(li_list) # ['上海', '广州']1.4
Crawling the value of Baidu search buttonimport urllib.request
from lxml import etree
url = 'http://www.baidu.com'
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36'
}
request = urllib.request.Request(url=url, headers=headers)
response = urllib.request.urlopen(request)
content = response.read().decode('utf-8')
tree = etree.HTML(content)
value = tree.xpath('//input[@id="su"]/@value')
print(value)
# 需求 下载的前十页的图片 # https://sc.chinaz.com/tupian/qinglvtupian.html 1 # https://sc.chinaz.com/tupian/qinglvtupian_page.html import urllib.request from lxml import etree def create_request(page): if (page == 1): url = 'https://sc.chinaz.com/tupian/qinglvtupian.html' else: url = 'https://sc.chinaz.com/tupian/qinglvtupian_' + str(page) + '.html' headers = { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.159 Safari/537.36', } request = urllib.request.Request(url=url, headers=headers) return request def get_content(request): response = urllib.request.urlopen(request) content = response.read().decode('utf-8') return content def down_load(content): # 下载图片 # urllib.request.urlretrieve('图片地址','文件的名字') tree = etree.HTML(content) name_list = tree.xpath('//div[@id="container"]//a/img/@alt') # 一般设计图片的网站都会进行懒加载 src_list = tree.xpath('//div[@id="container"]//a/img/@src2') print(src_list) for i in range(len(name_list)): name = name_list[i] src = src_list[i] url = 'https:' + src urllib.request.urlretrieve(url=url, filename='./loveImg/' + name + '.jpg') if __name__ == '__main__': start_page = int(input('请输入起始页码')) end_page = int(input('请输入结束页码')) for page in range(start_page, end_page + 1): # (1) 请求对象的定制 request = create_request(page) # (2)获取网页的源码 content = get_content(request) # (3)下载 down_load(content)2. JsonPath2.1 pip installation
pip install jsonpath
2.2 Use of jsonpathobj = json.load(open('json文件', 'r', encoding='utf‐8'))
ret = jsonpath.jsonpath(obj, 'jsonpath语法')
Comparison of JSONPath syntax elements and corresponding XPath elements:
Example:
jsonpath.json
{ "store": { "book": [ { "category": "修真", "author": "六道", "title": "坏蛋是怎样练成的", "price": 8.95 }, { "category": "修真", "author": "天蚕土豆", "title": "斗破苍穹", "price": 12.99 }, { "category": "修真", "author": "唐家三少", "title": "斗罗大陆", "isbn": "0-553-21311-3", "price": 8.99 }, { "category": "修真", "author": "南派三叔", "title": "星辰变", "isbn": "0-395-19395-8", "price": 22.99 } ], "bicycle": { "author": "老马", "color": "黑色", "price": 19.95 } } }
import json import jsonpath obj = json.load(open('jsonpath.json', 'r', encoding='utf-8')) # 书店所有书的作者 author_list = jsonpath.jsonpath(obj, '$.store.book[*].author') print(author_list) # ['六道', '天蚕土豆', '唐家三少', '南派三叔'] # 所有的作者 author_list = jsonpath.jsonpath(obj, '$..author') print(author_list) # ['六道', '天蚕土豆', '唐家三少', '南派三叔', '老马'] # store下面的所有的元素 tag_list = jsonpath.jsonpath(obj, '$.store.*') print( tag_list) # [[{'category': '修真', 'author': '六道', 'title': '坏蛋是怎样练成的', 'price': 8.95}, {'category': '修真', 'author': '天蚕土豆', 'title': '斗破苍穹', 'price': 12.99}, {'category': '修真', 'author': '唐家三少', 'title': '斗罗大陆', 'isbn': '0-553-21311-3', 'price': 8.99}, {'category': '修真', 'author': '南派三叔', 'title': '星辰变', 'isbn': '0-395-19395-8', 'price': 22.99}], {'author': '老马', 'color': '黑色', 'price': 19.95}] # store里面所有东西的price price_list = jsonpath.jsonpath(obj, '$.store..price') print(price_list) # [8.95, 12.99, 8.99, 22.99, 19.95] # 第三个书 book = jsonpath.jsonpath(obj, '$..book[2]') print(book) # [{'category': '修真', 'author': '唐家三少', 'title': '斗罗大陆', 'isbn': '0-553-21311-3', 'price': 8.99}] # 最后一本书 book = jsonpath.jsonpath(obj, '$..book[(@.length-1)]') print(book) # [{'category': '修真', 'author': '南派三叔', 'title': '星辰变', 'isbn': '0-395-19395-8', 'price': 22.99}] # 前面的两本书 book_list = jsonpath.jsonpath(obj, '$..book[0,1]') # book_list = jsonpath.jsonpath(obj,'$..book[:2]') print( book_list) # [{'category': '修真', 'author': '六道', 'title': '坏蛋是怎样练成的', 'price': 8.95}, {'category': '修真', 'author': '天蚕土豆', 'title': '斗破苍穹', 'price': 12.99}] # 条件过滤需要在()的前面添加一个? # 过滤出所有的包含isbn的书。 book_list = jsonpath.jsonpath(obj, '$..book[?(@.isbn)]') print( book_list) # [{'category': '修真', 'author': '唐家三少', 'title': '斗罗大陆', 'isbn': '0-553-21311-3', 'price': 8.99}, {'category': '修真', 'author': '南派三叔', 'title': '星辰变', 'isbn': '0-395-19395-8', 'price': 22.99}] # 哪本书超过了10块钱 book_list = jsonpath.jsonpath(obj, '$..book[?(@.price>10)]') print( book_list) # [{'category': '修真', 'author': '天蚕土豆', 'title': '斗破苍穹', 'price': 12.99}, {'category': '修真', 'author': '南派三叔', 'title': '星辰变', 'isbn': '0-395-19395-8', 'price': 22.99}]3. BeautifulSoup3.1 Basic introduction1.Installation
pip install bs42.Import
from bs4 import BeautifulSoup3. Create object
- The file generated by the server response object soup = BeautifulSoup(response.read().decode() , 'lxml')
- Local file generation object soup = BeautifulSoup(open('1.html'), 'lxml')
3.2 Installation and creationNote: The default encoding format for opening files is gbk, so you need to specify the opening encoding format utf-8
1.根据标签名查找节点
soup.a 【注】只能找到第一个a
soup.a.name
soup.a.attrs
2.函数
(1).find(返回一个对象)
find('a'):只找到第一个a标签
find('a', title='名字')
find('a', class_='名字')
(2).find_all(返回一个列表)
find_all('a') 查找到所有的a
find_all(['a', 'span']) 返回所有的a和span
find_all('a', limit=2) 只找前两个a
(3).select(根据选择器得到节点对象)【推荐】
1.element
eg:p
2..class
eg:.firstname
3.#id
eg:#firstname
4.属性选择器
[attribute]
eg:li = soup.select('li[class]')
[attribute=value]
eg:li = soup.select('li[class="hengheng1"]')
5.层级选择器
element element
div p
element>element
div>p
element,element
div,p
eg:soup = soup.select('a,span')
3.3 Node positioning 1.根据标签名查找节点
soup.a 【注】只能找到第一个a
soup.a.name
soup.a.attrs
2.函数
(1).find(返回一个对象)
find('a'):只找到第一个a标签
find('a', title='名字')
find('a', class_='名字')
(2).find_all(返回一个列表)
find_all('a') 查找到所有的a
find_all(['a', 'span']) 返回所有的a和span
find_all('a', limit=2) 只找前两个a
(3).select(根据选择器得到节点对象)【推荐】
1.element
eg:p
2..class
eg:.firstname
3.#id
eg:#firstname
4.属性选择器
[attribute]
eg:li = soup.select('li[class]')
[attribute=value]
eg:li = soup.select('li[class="hengheng1"]')
5.层级选择器
element element
div p
element>element
div>p
element,element
div,p
eg:soup = soup.select('a,span')
3.5 Node information (1).获取节点内容:适用于标签中嵌套标签的结构
obj.string
obj.get_text()【推荐】
(2).节点的属性
tag.name 获取标签名
eg:tag = find('li)
print(tag.name)
tag.attrs将属性值作为一个字典返回
(3).获取节点属性
obj.attrs.get('title')【常用】
obj.get('title')
obj['title']
(1).获取节点内容:适用于标签中嵌套标签的结构
obj.string
obj.get_text()【推荐】
(2).节点的属性
tag.name 获取标签名
eg:tag = find('li)
print(tag.name)
tag.attrs将属性值作为一个字典返回
(3).获取节点属性
obj.attrs.get('title')【常用】
obj.get('title')
obj['title']
3.6 Usage example
bs4.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> <div> <ul> <li id="l1">张三</li> <li id="l2">李四</li> <li>王五</li> <a href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" " class="a1">google</a> <span>嘿嘿嘿</span> </ul> </div> <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百度</a> <div id="d1"> <span> 哈哈哈 </span> </div> <p id="p1" class="p1">呵呵呵</p> </body> </html>
from bs4 import BeautifulSoup # 通过解析本地文件 来将bs4的基础语法进行讲解 # 默认打开的文件的编码格式是gbk 所以在打开文件的时候需要指定编码 soup = BeautifulSoup(open('bs4.html', encoding='utf-8'), 'lxml') # 根据标签名查找节点 # 找到的是第一个符合条件的数据 print(soup.a) # <a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a> # 获取标签的属性和属性值 print(soup.a.attrs) # {'href': '', 'id': '', 'class': ['a1']} # bs4的一些函数 # (1)find # 返回的是第一个符合条件的数据 print(soup.find('a')) # <a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a> # 根据title的值来找到对应的标签对象 print(soup.find('a', title="a2")) # <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百度</a> # 根据class的值来找到对应的标签对象 注意的是class需要添加下划线 print(soup.find('a', class_="a1")) # <a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a> # (2)find_all 返回的是一个列表 并且返回了所有的a标签 print(soup.find_all('a')) # [<a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a>, <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百度</a>] # 如果想获取的是多个标签的数据 那么需要在find_all的参数中添加的是列表的数据 print(soup.find_all(['a','span'])) # [<a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a>, <span>嘿嘿嘿</span>, <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百</a><spa哈</span>] # limit的作用是查找前几个数据 print(soup.find_all('li', limit=2)) # [<li id="l1">张三</li>, <li id="l2">李四</li>] # (3)select(推荐) # select方法返回的是一个列表 并且会返回多个数据 print(soup.select('a')) # [<a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a>, <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百度</a>] # 可以通过.代表class 我们把这种操作叫做类选择器 print(soup.select('.a1')) # [<a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a>] print(soup.select('#l1')) # [<li id="l1">张三</li>] # 属性选择器---通过属性来寻找对应的标签 # 查找到li标签中有id的标签 print(soup.select('li[id]')) # [<li id="l1">张三</li>, <li id="l2">李四</li>] # 查找到li标签中id为l2的标签 print(soup.select('li[id="l2"]')) # [<li id="l2">李四</li>] # 层级选择器 # 后代选择器 # 找到的是div下面的li print(soup.select('div li')) # [<li id="l1">张三</li>, <li id="l2">李四</li>, <li>王五</li>] # 子代选择器 # 某标签的第一级子标签 # 注意:很多的计算机编程语言中 如果不加空格不会输出内容 但是在bs4中 不会报错 会显示内容 print(soup.select('div > ul > li')) # [<li id="l1">张三</li>, <li id="l2">李四</li>, <li>王五</li>] # 找到a标签和li标签的所有的对象 print(soup.select( 'a,li')) # [<li id="l1">张三</li>, <li id="l2">李四</li>, <li>王五</li>, <a class="a1" href="" id=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" ">google</a>, <a href="" title=" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" a2">百度</a>] # 节点信息 # 获取节点内容 obj = soup.select('#d1')[0] # 如果标签对象中 只有内容 那么string和get_text()都可以使用 # 如果标签对象中 除了内容还有标签 那么string就获取不到数据 而get_text()是可以获取数据 # 我们一般情况下 推荐使用get_text() print(obj.string) # None print(obj.get_text()) # 哈哈哈 # 节点的属性 obj = soup.select('#p1')[0] # name是标签的名字 print(obj.name) # p # 将属性值左右一个字典返回 print(obj.attrs) # {'id': 'p1', 'class': ['p1']} # 获取节点的属性 obj = soup.select('#p1')[0] # print(obj.attrs.get('class')) # ['p1'] print(obj.get('class')) # ['p1'] print(obj['class']) # ['p1']3.7 Parse Starbucks product name
import urllib.request
url = 'https://www.starbucks.com.cn/menu/'
response = urllib.request.urlopen(url)
content = response.read().decode('utf-8')
from bs4 import BeautifulSoup
soup = BeautifulSoup(content,'lxml')
# //ul[@class="grid padded-3 product"]//strong/text()
# 一般先用xpath方式通过google插件写好解析的表达式
name_list = soup.select('ul[class="grid padded-3 product"] strong')
for name in name_list:
print(name.get_text())
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