Python xpath,JsonPath,bs4怎么使用
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1.xpath
1.1 xpath使用
google提前安装xpath插件，按ctrl + shift + x 出现小黑框
安装lxml库
pip install lxml ‐i https://pypi.douban.com/simple导入lxml.etree
from lxml import etreeetree.parse() 解析本地文件
html_tree = etree.parse('XX.html')etree.HTML() 服务器响应文件
html_tree = etree.HTML(response.read().decode('utf‐8').html_tree.xpath(xpath路径)
1.2 xpath基本语法
路径查询
查找所有子孙节点，不考虑层级关系
找直接子节点
谓词查询
//div[@id] //div[@id="maincontent"]属性查询
//@class模糊查询
//div[contains(@id, "he")] //div[starts‐with(@id, "he")]内容查询
//div/h2/text()逻辑运算
//div[@id="head" and @class="s_down"] //title | //price1.3 示例
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lili_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lili_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 爬取百度搜索按钮的value
import urllib.requestfrom lxml import etreeurl = '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)
5 爬取站长素材的图片
# 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.htmlimport urllib.requestfrom lxml import etreedef 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 requestdef get_content(request): response = urllib.request.urlopen(request) content = response.read().decode('utf-8') return contentdef 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 class="lazy" data-src_list = tree.xpath('//div[@id="container"]//a/img/@class="lazy" data-src2') print(class="lazy" data-src_list) for i in range(len(name_list)): name = name_list[i] class="lazy" data-src = class="lazy" data-src_list[i] url = 'https:' + class="lazy" data-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. JsonPath
2.1 pip安装
pip install jsonpath2.2 jsonpath的使用
obj = json.load(open('json文件', 'r', encoding='utf‐8')) ret = jsonpath.jsonpath(obj, 'jsonpath语法')JSONPath语法元素和对应XPath元素的对比：
示例：
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 jsonimport jsonpathobj = 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, '$.store.*')print( tag_list) # [[{'category': '修真', 'author': '六道', 'title': '坏蛋是怎样练成的', 'price': 8.95}, {'category': '修真', 'author': '天蚕土豆', 'title': '斗破苍穹', 'price': 12.99}, {'category': '修真', 'author': '唐家三少', 'title': '斗罗大陆', 'isbn': '0-553-21311-3', 'price': 8.99}, {'category': '修真', 'author': '南派三叔', 'title': '星辰变', 'isbn': '0-395-19395-8', 'price': 22.99}], {'author': '老马', 'color': '黑色', 'price': 19.95}]# store里面所有东西的priceprice_list = jsonpath.jsonpath(obj, '$.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. BeautifulSoup
3.1 基本简介
安装
pip install bs4
导入
from bs4 import BeautifulSoup
创建对象
服务器响应的文件生成对象 soup = BeautifulSoup(response.read().decode(), 'lxml')
本地文件生成对象 soup = BeautifulSoup(open('1.html'), 'lxml')
注意：默认打开文件的编码格式gbk所以需要指定打开编码格式utf-8
3.2 安装以及创建
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.#ideg:#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 节点定位
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.#ideg:#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 节点信息
(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 使用示例
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liprint(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) # Noneprint(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 解析星巴克产品名称
import urllib.requesturl = 'https://www.starbucks.com.cn/menu/'response = urllib.request.urlopen(url)content = response.read().decode('utf-8')from bs4 import BeautifulSoupsoup = 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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