简易版python爬虫--通过关键字爬取网页_关键词爬虫

背景：
帮同学写了个爬虫程序，特此记录，怕以后忘了
这里是爬取百度https://www.baidu.com
不为什么，主要就是百度老实，能爬，爬着简单，爬着不犯法。。。

关键字爬取基本模板：

import requests
from bs4 import BeautifulSoup
import random
import time

def searchbaidu(keyword):
		url = f"https://www.baidu.com/s?wd={keyword}"
        user_agents = [
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edge/20.10240.16384 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/85.0.564.44 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.109 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.57 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/79.0.309.68 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/78.0.276.19 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/77.0.235.9 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/75.0.139.8 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/74.1.96.24 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/73.0.3683.75 Safari/537.36'
        ]
        headers = {
            'User-Agent': random.choice(user_agents)
        }

        response = requests.get(url, headers=headers)
        time.sleep(random.uniform(0.5, 3))  # 设置访问频率限制
        soup = BeautifulSoup(response.content, "html.parser")
        results = soup.find_all("div", class_="result")
        for result in results:
            try:
                title = result.find("h3").text
                link = result.find("a")["href"]
                print(title)
                print(link)
            except:
                continue
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说明：

随机用户，反反爬虫

这个程序是有一点小优化的，主要就是进行了一点点小小的反反爬虫措施
如：

		user_agents = [
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edge/20.10240.16384 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/85.0.564.44 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.109 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.57 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/79.0.309.68 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/78.0.276.19 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/77.0.235.9 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/75.0.139.8 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/74.1.96.24 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/73.0.3683.75 Safari/537.36'
        ]
        headers = {
            'User-Agent': random.choice(user_agents)
        }
        time.sleep(random.uniform(0.5, 3))  # 设置访问频率限制
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这一步是为了获取一个请求对象，说白了就是模拟一个用户来访问，由此避开百度的反爬机制捏。不过百度这样好爬，也方便了咱们这些初学者学习嘛~
综上，通过随机获取列表里的数值来模拟出随机的访客

获取数据

		response = requests.get(url, headers=headers)
        soup = BeautifulSoup(response.content, "html.parser")
        results = soup.find_all("div", class_="result")
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requests.get(url, headers=headers)就是以headers的身份获取链接里面的内容

BeautifulSoup(response.content, “html.parser”)就是提取出内容里面的html部分

soup.find_all(“div”, class_=“result”)就是寻找html里所有class为result的div。

展示数据：

        for result in results:
            try:
                title = result.find("h3").text
                link = result.find("a")["href"]
                print(title)
                print(link)
            except:
                continue
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title = result.find(“h3”).text
link = result.find(“a”)[“href”]
result.find()也就是寻找标签为（）里面内容的东西，这里也就不意义赘述了

总代码：

import requests
from bs4 import BeautifulSoup
import random
import time

def searchbaidu(keyword):
		url = f"https://www.baidu.com/s?wd={keyword}"
        user_agents = [
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edge/20.10240.16384 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/85.0.564.44 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.109 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/80.0.361.57 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/79.0.309.68 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/78.0.276.19 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/77.0.235.9 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/75.0.139.8 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/74.1.96.24 Safari/537.36',
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Edg/73.0.3683.75 Safari/537.36'
        ]
        headers = {
            'User-Agent': random.choice(user_agents)
        }

        response = requests.get(url, headers=headers)
        time.sleep(random.uniform(0.5, 3))  # 设置访问频率限制
        soup = BeautifulSoup(response.content, "html.parser")
        results = soup.find_all("div", class_="result")
        for result in results:
            try:
                title = result.find("h3").text
                link = result.find("a")["href"]
                print(title)
                print(link)
            except:
                continue
 searchbaidu("python")
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调用函数寻找关键字为"python"的内容
结果：

大概就这样了~~