文章目录
python爬虫—数据解析
https://live.csdn.net/list/CSDNedu
-
数据解析的作用
- 可以帮助我们实现聚焦爬虫
-
数据解析的实现方式
- 正则
- bs4
- xpath
- pyquery
-
数据解析的通用原理
- 问题1:聚集爬虫爬取的数据是存储在哪里的?
- 都被存储在了相关的标签中
- 定位标签
- 取文本或者属性
- 都被存储在了相关的标签中
- 问题1:聚集爬虫爬取的数据是存储在哪里的?
正则(不用)
如何获取图片?
import requests
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
# 如何爬取图片
# 第一种方式
# 图片地址
url = 'https://pic.qiushibaike.com/system/pictures/12389/123894177/medium/KPFH2OYHBAL1925C.jpg'
img_data = requests.get(url=url, headers=headers).content # 返回的是byte类型的数据
with open('./img.jpg', 'wb') as fp:
fp.write(img_data)
# 第二种方式
# 弊端:不能使用UA伪装
from urllib import request
url = 'https://pic.qiushibaike.com/system/pictures/12389/123894177/medium/KPFH2OYHBAL1925C.jpg'
request.urlretrieve(url, filename='./qiutu.jpg')
获取qiushibaike图片数据
import requests
import re
import os
from urllib import request
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
# 创建文件夹
dirName = './imgLibs'
if not os.path.exists(dirName):
os.mkdir(dirName)
"""
爬取1~3页的所以图片:
https://www.qiushibaike.com/imgrank/page/1/
https://www.qiushibaike.com/imgrank/page/2/
https://www.qiushibaike.com/imgrank/page/3/
1. 使用通用爬虫将前3页对应的数据拿到
"""
"""
<div class="thumb">
<a href="/article/123898296" target="_blank">
<img src="//pic.qiushibaike.com/system/pictures/12389/123898296/medium/PK7O8YIG418SSOS1.jpg" alt="糗事#123898296" class="illustration" width="100%" height="auto">
</a>
</div>
ex = '<div class="thumb">.*?<img src="(.*?)" alt.*?</div>'
"""
# 设定一个通用的url模板,模板是不可变的
url = 'https://www.qiushibaike.com/imgrank/page/%d/'
for page in range(1, 4):
new_url = format(url % page)
# print(new_url)
page_text = requests.get(url=new_url,headers=headers).text # 每一个页码对应的页面源码数据
# print(page_text)
# 在通用爬虫的基础上实现聚焦爬虫(每一个页面源码数据种解析处图片数据)
ex = '<div class="thumb">.*?<img src="(.*?)" alt.*?</div>'
img_src = re.findall(ex, page_text, re.S) # 有回车正则失效, re.S 忽略回车
for src in img_src:
src = 'https:' + src
img_name = src.split('/')[-1]
img_path = dirName + '/' + img_name # ./imgLibs/xxx.jpg
print(src)
print()
try:
request.urlretrieve(src, filename=img_path)
print(img_name, '下载成功!!!')
except:
print(src, "404 Not Found!")
bs4解析(一般使用)
-
原理
- 实例化一个BeautifulSoup的对象,需要将即将被解析的页面源码数据加载到该对象中
- 调用BeautifulSoup对象中的相关方法和属性进行标签定位和数据提取
-
环境的安装
- pip install bs4
- pip install lxml
-
BeautifulSoup的实例化:
- BeautifulSoup(fp, ‘lxml’):将本地存储的一个html文档中的数据加载到实例化号的BeautifulSoup对象中
- BeautifulSoup(‘page_text’, ‘lxml’):将互联网上获取的页面源码加载到实例化号的BeautifulSoup对象中
-
定位标签的操作
- soup.div:定位到第一个出现的tagName标签
- 属性定位:
- soup.find(‘div’, class_=‘bg-gj-w’)
- soup.find(‘a’, id=‘result_more_appli_ABC’) 返回定位到的标签
- soup.find_all(‘div’) 找到所有的div,返回的是一个列表
- 选择器定位:
- 返回的是列表
- print(soup.select(’.bg-gj-w’)) # 类选择器
- print(soup.select(’#result_more_appli_ABC’)) # id择器
- print(soup.select(’.class > ul > li’)) # id择器 一个大于号代表一级
- print(soup.select(’.class li’)) # 层级择器 一个空格代表多级
-
取文本
扫描二维码关注公众号,回复: 12653095 查看本文章- res.string:获取直系的文本内容
- res.text:获取所有的文本内容
-
取属性
- res[‘href’]
from bs4 import BeautifulSoup
fp = open('jay.html', 'r', encoding='utf-8')
soup = BeautifulSoup(fp, 'lxml')
# print(soup)
# print(soup.div)
# print(soup.find('div', class_='bg-gj-w'))
# print(soup.find('a', id='result_more_appli_ABC'))
# print(soup.find_all('div')) # 找到所有的div,返回的是一个列表
#
# print(soup.select('.bg-gj-w')) # 类选择器
# print(soup.select('#result_more_appli_ABC')) # id择器
# print(soup.select('.class > ul > li')) # id择器 一个大于号代表一级
# print(soup.select('.class li')) # 层级择器 一个空格代表多级
res = soup.select('#sogou_feedback ')[0]
print(res)
print(res.string) # 取文本
print(res.text)
print(res['href'])
bs4解析获取三国演义小说
https://www.shicimingju.com/book/sanguoyanyi.html
"""
爬取三国演义整篇内容(章节名称和章节列表)
https://www.shicimingju.com/book/sanguoyanyi.html
"""
import requests
from bs4 import BeautifulSoup
fp = open('sangup.txt', 'w', encoding='utf-8')
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
main_url = 'https://www.shicimingju.com/book/sanguoyanyi.html'
page_text = requests.get(url=main_url, headers=headers).text
# 解析出章节名称和章节详情页的url
soup = BeautifulSoup(page_text, 'lxml')
a_list = soup.select('.book-mulu > ul > li > a') # 返回的列表中存储的是一个个的a标签
for a in a_list:
title = a.string
detail_url = 'https://www.shicimingju.com' + a['href']
print(detail_url)
detail_page_text = requests.get(detail_url, headers=headers).text
# 解析详情页中的章节内容
soup = BeautifulSoup(detail_page_text, 'lxml')
content = soup.find('div', class_='chapter_content').text
fp.write(title+':'+content+'\n')
print(title, '下载成功!')
fp.close()
神级龙卫小说获取
import requests
from bs4 import BeautifulSoup
fp = open('shenji.txt', 'w', encoding='utf-8')
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
main_url = 'http://m.ajnnan.com/17_17514/all.html'
page_text = requests.get(url=main_url, headers=headers)
page_text.encoding = 'utf-8'
page_text = page_text.text
# 解析出章节名称和章节详情页的url
soup = BeautifulSoup(page_text, 'lxml')
a_list = soup.select('#chapterlist > p > a') # 返回的列表中存储的是一个个的a标签
for a in a_list[1:]:
title = a.string
detail_url = 'http://m.ajnnan.com' + a['href']
# print(detail_url, title)
detail_page_text = requests.get(detail_url, headers=headers)
detail_page_text.encoding = 'utf-8'
detail_page_text = detail_page_text.text
# 解析详情页中的章节内容
soup = BeautifulSoup(detail_page_text, 'lxml')
content = soup.find('div', id='chaptercontent').text
next_url = 'http://m.ajnnan.com' + soup.find('a', id='pb_next')['href']
# print(next_url)
detail_page_text1 = requests.get(next_url, headers=headers)
detail_page_text1.encoding = 'utf-8'
# print(detail_page_text1)
detail_page_text1 = detail_page_text1.text
soup1 = BeautifulSoup(detail_page_text1, 'lxml')
content = content + soup1.find('div', id='chaptercontent').text
next_url2 = 'http://m.ajnnan.com' + soup1.find('a', id='pb_next')['href']
detail_page_text2 = requests.get(next_url2, headers=headers)
detail_page_text2.encoding = 'utf-8'
detail_page_text2 = detail_page_text2.text
soup2 = BeautifulSoup(detail_page_text2, 'lxml')
content = content + soup2.find('div', id='chaptercontent').text
fp.write(title+':'+content+'\n')
print(title, '下载成功!')
fp.close()
xpath解析(重点使用)
浏览器直接F12–>在elements中找到对应的标签–>右击–>copy–>copy xpath
-
原理
- 实例化一个etree的对象,然后将即将被解析的页面源码加载到该对象中
- 使用etree对象中的xpath方法结合不同形式的xpath表达式实现标签定位和数据提取
-
环境安装:
- pip install lxml
-
etree对象的实例化:
- etree.parse(‘test.html’)
- etree.HTML(page_text)
-
xpath表达式
- 最左侧的/表示:xpath表达式一定要从根标签逐层进行标签查找和定位
- 最左侧的//表示:xpath表达式可以从任意位置定位标签
- 非最左侧的/表示:表示一个层级
- 非最左侧的//表示:表示多个层级
- 属性定位://tagName[@attrName=“value”]
- 索引定位://tagName[index] 索引是从1开始
-
取文本
- /text(): 直系文本内容
- //text(): 所有的文本内容
-
取属性
- /@attrName
from lxml import etree
parser = etree.HTMLParser(encoding='utf-8') # html代码书写不规范,不符合xml解析器的使用规范。加上这句话后解决
tree = etree.parse('jay.html', parser=parser)
# print(tree)
# print(tree.xpath('/html/body/div/p')) # 绝对
# print(tree.xpath('//p')) # 所有p
# print(tree.xpath('/html/body//p')) # html/body下的所有p
#
# print(tree.xpath('//div[@class="song"]')) # 属性定位
# print(tree.xpath('//li[7]')) # 从0开始
print(tree.xpath('//a[@class="feng"]/text()')[0]) # 列表 那元素
print(tree.xpath('//a[@class="feng"]/@href')[0]) # 列表 那元素
获取糗事百科中的文字内容
https://www.qiushibaike.com/text/
"""
获取糗事百科中的文字内容
https://www.qiushibaike.com/text/
"""
import requests
from lxml import etree
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
url = 'https://www.qiushibaike.com/text/'
page_text = requests.get(url=url, headers=headers).text
# 解析内容
tree = etree.HTML(page_text)
div_list = tree.xpath('//div[@class="col1 old-style-col1"]/div')
# print(len(div_list))
for div in div_list:
author = div.xpath('./div[1]/a[2]/h2/text()')[0] # 实现局部解析,前边一定要写个. 否则只写/就是全局的啦
content = div.xpath('./a[1]/div/span//text()')
content = ''.join(content)
print(author, content)
批量获取4K美女图片
http://pic.netbian.com/4kmeinv/
"""
### 获取4K美女图片
http://pic.netbian.com/4kmeinv/
解决中文乱码问题
第一页:http://pic.netbian.com/4kmeinv/ 需要单独处理
第二页:http://pic.netbian.com/4kmeinv/index_2.html
"""
import requests
import os
from urllib import request
from lxml import etree
dirName = 'meinvLibs'
if not os.path.exists(dirName):
os.mkdir(dirName)
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
url = 'http://pic.netbian.com/4kmeinv/index_%d.html'
for page in range(1, 11):
if page == 1:
new_url = 'http://pic.netbian.com/4kmeinv/'
else:
new_url = format(url%page)
# print(new_url)
page_text = requests.get(url=new_url, headers=headers).text
tree = etree.HTML(page_text)
a_list = tree.xpath('//div[@class="slist"]/ul/li/a')
for a in a_list:
img_src = 'http://pic.netbian.com' + a.xpath('./img/@src')[0]
img_name = a.xpath('./b/text()')[0]
img_name = img_name.encode('iso-8859-1').decode('gbk') # 通用方式解决中文乱码问题
# print(img_src, img_name) # 无中文乱码
imgPath = dirName + '/' + img_name + '.jpg'
request.urlretrieve(img_src, filename=imgPath)
print(img_name+'.jpg', '下载成功!')
作业:对免费的简历模板进行获取和保存
https://sc.chinaz.com/jianli/free.html 免费的简历模板进行获取和保存
"""
获取免费简历模板
https://sc.chinaz.com/jianli/free.html
"""
import requests
import os
from lxml import etree
dirName = 'jianliLibs'
if not os.path.exists(dirName):
os.mkdir(dirName)
headers = {
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36'
}
url = 'https://sc.chinaz.com/jianli/free_%d.html'
page_text = requests.get(url=url, headers=headers).text
tree = etree.HTML(page_text)
for page in range(1, 3):
if page == 1:
new_url = 'https://sc.chinaz.com/jianli/free.html'
else:
new_url = format(url%page)
page_text = requests.get(url=new_url, headers=headers).text
tree = etree.HTML(page_text)
a_list = tree.xpath('//*[@id="main"]/div/div/p/a')
for a in a_list:
url_ = 'https:' + a.xpath('./@href')[0]
name = a.xpath('./text()')[0]
name = name.encode('iso-8859-1').decode('utf-8') # 通用方式解决中文乱码问题
# print(url_, name)
new_page_text = requests.get(url=url_, headers=headers).text
tree = etree.HTML(new_page_text)
download_url = tree.xpath('//*[@id="down"]/div[2]/ul/li[1]/a/@href')[0]
res = requests.get(url=download_url)
path = dirName + '/' + name + '.rar'
with open(path, 'wb') as fp: # 以二进制的形式写,不需要指定编码格式,获取到的content是bytes
fp.write(res.content)
print(name, '下载成功!')