一、访问网站20次

import requestsfrom bs4 import BeautifulSoup#调用函数r = requests.get("http://www.baidu.com")#输入网站名字r.encoding = "utf-8"soup = BeautifulSoup(r.text)for i in range(20):#控制循环，访问网站20次即可。    print(soup.head)    print("\n")    print(i+1)    print("\n")

通过用for循环，来控制访问次数，效果如下：

 

 二、爬虫

 

 

import requestsfrom bs4 import BeautifulSoupalluniv = []def getHTMLText(url):#访问网站并获取内容    try:        r = requests.get(url,timeout = 30)        r.raise_for_status()        r.encoding = 'utf-8'        return r.text    except:        return "error"def fillunivlist(soup):#获取我们需要的内容    data=soup.find_all('tr')    for tr in data:        ltd =tr.find_all('td')        if len(ltd)==0:            continue        singleuniv=[]        for td in ltd:            singleuniv.append(td.string)        alluniv.append(singleuniv)def printunivlist(num):#建立这个排名表格    print("{:^4}{:^10}{:^5}{:^8}{:^10}".format("排名","学校名字","省份","总分","培养规模"))    for i in range(num):        u=alluniv[i]        print("{:^4}{:^10}{:^5}{:^8}{:^10}".format(u[0],u[1],u[2],u[3],u[6]))def main(num):#输出num个数的大学排名    url = "http://www.zuihaodaxue.cn/zuihaodaxuepaiming2019.html"    html=getHTMLText(url)    soup=BeautifulSoup(html,"html.parser")    fillunivlist(soup)    printunivlist(num)main(100)

 效果如下：