爬取链接:http://www.zuihaodaxue.com/zuihaodaxuepaiming2019.html
程序设计结构:
1.获取大学排名网页内容 getHTMLText()
2.提取网页内容中信息到合适的数据结构 fillUnivList()
3.利用数据结构展示并输出结果 printUnivList()
完整代码 Python3.7 pycharm
import requests
from bs4 import BeautifulSoup
import bs4
def getHTMLText(url):
try:
r=requests.get(url,timeout=30)
r.raise_for_status()
r.encoding=r.apparent_encoding
return r.text
except:
return ""
def fillUnivList(ulist,html):
soup = BeautifulSoup(html,"html.parser")
for tr in soup.find('tbody').children:
if isinstance(tr,bs4.element.Tag):
tds=tr('td')#等价于tr.find_all('td')
ulist.append([tds[0].string,tds[1].string,tds[2].string])
def printUnivList(ulist,num):
print("{:^10}\t{:^6}\t{:^10}".format("排名","学校","地区"))
for i in range (num):
u=ulist[i]
print("{:^10}\t{:^6}\t{:^10}".format(u[0],u[1],u[2]))
def main():
uinfo=[]
url="http://www.zuihaodaxue.com/zuihaodaxuepaiming2019.html"
html=getHTMLText(url)
fillUnivList(uinfo,html)
printUnivList(uinfo,20)
if __name__ == '__main__':
main()
中文对齐格式优化:
def printUnivList(ulist,num):
print("{:^10}\t{:^6}\t{:^10}".format("排名","学校","地区"))
for i in range (num):
u=ulist[i]
print("{:^10}\t{:^6}\t{:^10}".format(u[0],u[1],u[2]))
修改为
def printUnivList(ulist, num):
print("{0:^10}\t{1:{3}^10}\t{2:^10}".format("排名", "学校", "地区",chr(12288)))
for i in range(num):
u = ulist[i]
print("{0:^10}\t{1:{3}^10}\t{2:^10}".format(u[0], u[1], u[2],chr(12288)))
修改过程中可能出现 IndexError: tuple index out of range
所以上下一定对齐,chr()是在format 里面,以及其写法。