Python爬虫必备技巧详细总结
自定义函数
import requests from bs4 import BeautifulSoup headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'} def baidu(company): url = 'https://www.baidu.com/s?rtt=4&tn=news&word=' + company print(url) html = requests.get(url, headers=headers).text s = BeautifulSoup(html, 'html.parser') title=s.select('.news-title_1YtI1 a') for i in title: print(i.text) # 批量调用函数 companies = ['腾讯', '阿里巴巴', '百度集团'] for i in companies: baidu(i)
批量输出多个搜索结果的标题
结果保存为文本文件
import requests from bs4 import BeautifulSoup headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'} def baidu(company): url = 'https://www.baidu.com/s?rtt=4&tn=news&word=' + company print(url) html = requests.get(url, headers=headers).text s = BeautifulSoup(html, 'html.parser') title=s.select('.news-title_1YtI1 a') fl=open('test.text','a', encoding='utf-8') for i in title: fl.write(i.text + '\n') # 批量调用函数 companies = ['腾讯', '阿里巴巴', '百度集团'] for i in companies: baidu(i)
写入代码
fl=open('test.text','a', encoding='utf-8') for i in title: fl.write(i.text + '\n')
异常处理
for i in companies: try: baidu(i) print('运行成功') except: print('运行失败')
写在循环中 不会让程序停止运行 而会输出运行失败
休眠时间
import time for i in companies: try: baidu(i) print('运行成功') except: print('运行失败') time.sleep(5)
time.sleep(5)
括号里的单位是秒
放在什么位置 则在什么位置休眠(暂停)
爬取多页内容
百度搜索腾讯
切换到第二页
去掉多多余的
https://www.baidu.com/s?wd=腾讯&pn=10
分析出
https://www.baidu.com/s?wd=腾讯&pn=0 为第一页
https://www.baidu.com/s?wd=腾讯&pn=10 为第二页
https://www.baidu.com/s?wd=腾讯&pn=20 为第三页
https://www.baidu.com/s?wd=腾讯&pn=30 为第四页
..........
代码
from bs4 import BeautifulSoup import time headers={'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0'} def baidu(c): url = 'https://www.baidu.com/s?wd=腾讯&pn=' + str(c)+'0' print(url) html = requests.get(url, headers=headers).text s = BeautifulSoup(html, 'html.parser') title=s.select('.t a') for i in title: print(i.text) for i in range(10): baidu(i) time.sleep(2)
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