Question

您好我是Python的新手，我想弄清楚为什么每次加载新页面并在while循环期间抓取时，我的列表会覆盖以前的元素。先感谢您。

def scrapeurls():
    domain = "https://domain234dd.com"
    count = 0

    while count < 10:

        page = requests.get("{}{}".format(domain, count))
        soup = BeautifulSoup(page.content, 'html.parser')
        data = soup.findAll('div', attrs={'class': 'video'})

        urls = []

        for div in data:
            links = div.findAll('a')
            for a in links:
                urls.append(a['href'])
                print(a['href'])

        print(count)
        count += 1

Answer 1

因为您在循环的每次迭代中将urls重置为空列表。你应该把它移到循环之前。

（注意，整个事情会更好地表达为for循环。）

Answer 2

您需要在循环之前初始化URL列表。如果在循环内部初始化，则每次都将其设置为空。

Answer 3

domain = "https://domain234dd.com"
count = 0

urls = []
while count < 10:

    page = requests.get("{}{}".format(domain, count))
    soup = BeautifulSoup(page.content, 'html.parser')
    data = soup.findAll('div', attrs={'class': 'video'})

    for div in data:
        links = div.findAll('a')
        for a in links:
            urls.append(a['href'])
            print(a['href'])

    print(count)
    count += 1

Python - 以前的列表元素在while循环期间被新元素覆盖

3 个答案: