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)

来源：https://blog.csdn.net/weixin_42403632/article/details/120884472