python - 迭代时出现索引错误

Question

我在迭代时遇到 IndexError 问题。该程序运行良好，直到一切完成，不再有“子网站”可访问，然后崩溃，因此无法保存在 .txt 中。

回溯(最近一次调用)

newUrl = nextpage[counter]['href']
IndexError: list index out of range

代码

from urllib.request import urlopen, Request
from bs4 import BeautifulSoup
import json
class Olx():

    def __init__(self, url):
        self.url = url

    def getPrice(self):
        """Get prices from olx"""
        html = urlopen(self.url)
        bs = BeautifulSoup(html, 'html.parser')
        price = bs.findAll('p', class_='price')
        return price

    def nextPage(self):
        """Go to the next page"""
        html = urlopen(self.url)
        bs = BeautifulSoup(html, 'html.parser')
        pageButton = bs.findAll('a', {'class': 'block br3 brc8 large tdnone lheight24'})
        try:
            return pageButton
        except AttributeError:
            None
        else:
            return pageButton

    

olxprices = Olx('https://www.olx.pl/nieruchomosci/mieszkania/wynajem/olsztyn/').getPrice()
nextpage = Olx('https://www.olx.pl/nieruchomosci/mieszkania/wynajem/olsztyn/').nextPage()
counter = 0

output = []
while len(nextpage) > 0:
    for price in olxprices:
        output.append(price.get_text().strip())
        print(price.get_text().strip())
    newUrl = nextpage[counter]['href']
    olxprices = Olx(newUrl).getPrice()
    counter += 1

print(output)

Answer 1

len(nextpage) 永远不会改变，因此 while 循环永远不会结束，最终 counter 索引会超过 nextpage 的末尾。相反，请执行以下操作:

for page in nextpage:
    for price in olxprices:
        output.append(price.get_text().strip())
        print(price.get_text().strip())
    newUrl = page['href']
    olxprices = Olx(newUrl).getPrice()