Python之从 URL 获取数据的程序的 IndexError

当我尝试执行该程序时，我不断收到 IndexError:列表索引超出范围。这是我的代码:

''' This program accesses the Bloomberg US Stock information page. 
    It uses BeautifulSoup to parse the html and then finds the elements with the top 20 stocks. 
    It finds the the stock name, value, net change, and percent change.  
''' 
 
import urllib 
from urllib import request 
from bs4 import BeautifulSoup 
 
 
# get the bloomberg stock page 
bloomberg_url = "http://www.bloomberg.com/markets/stocks/world-indexes/americas" 
 
try: 
    response = request.urlopen(bloomberg_url) 
except urllib.error.URLError as e: 
    if hasattr(e, 'reason'): 
        print('We failed to reach a server.') 
        print('Reason: ', e.reason) 
    elif hasattr(e, 'code'): 
        print('The server couldn\'t fulfill the request.') 
        print('Error code: ', e.code) 
else: 
    # the url request was successful 
    html = response.read().decode('utf8') 
 
    # use the BeautifulSoup parser to create the beautiful soup object with html structure 
    bloomsoup = BeautifulSoup(html, 'html.parser') 
    pagetitle = bloomsoup.title.get_text() 
 
    # the 20 stocks are stored in the first 10 "oddrow" tr tags 
    #   and the 10 "evenrow" tr tags 
    oddrows = bloomsoup.find_all("tr",class_="oddrow") 
    evenrows = bloomsoup.find_all("tr",class_="evenrow") 
 
    # alternate odd and even rows to put all 20 rows together 
    allrows=[] 
    for i in range(12): 
        allrows.append(oddrows[i]) 
        allrows.append(evenrows[i]) 
    allrows.append(oddrows[12]) 
 
    # iterate over the BeautifulSoup tr tag objects and get the team items into a dictionary 
    stocklist = [ ] 
    for item in allrows: 
        stockdict = { } 
        stockdict['stockname'] = item.find_all('a')[1].get_text() 
        stockdict['value'] = item.find("td",class_="pr-rank").get_text() 
        stockdict['net'] = item.find('span',class_="pr-net").get_text() 
        stockdict['%'] = item.find('td',align="center").get_text() 
        stocklist.append(stockdict) 
 
    # print the title of the page 
    print(pagetitle, '\n') 
 
    # print out all the teams 
    for stock in stocklist: 
        print('Name:', stock['stockname'], 'Value:', stock['value'], 'Net Change:', stock['net'],\ 
            'Percent Change:', stock['%']) 

请您参考如下方法:

oddrows 和 evenrows 根据您的评论只有 10 个元素。

the 20 stocks are stored in the first 10 "oddrow" tr tags and the 10 "evenrow" tr tags

但是你循环了 12 次而不是 10 次:for i in range(12):

将 12 更改为 10，它应该可以工作。

旁注:我不建议对该值进行硬编码。

你可以替换

allrows=[] 
for i in range(12): 
    allrows.append(oddrows[i]) 
    allrows.append(evenrows[i]) 

与

allrows=[] 
for x,y in zip(oddrows,evenrows): 
    allrows.append(x) 
    allrows.append(y)