如何修复类型错误：'NoneType'对象不可迭代

Question

我想用Beautiful Soup来抓取一些信息，我把一个try…except在for循环中，但它似乎不是很有效。我一定是做错了什么，但我不知道在哪里。

这从一个名为occupations_list的URL列表中获取html。URL示例:https://candidat.pole-emploi.fr/offres/emploi/horticulteur/s1m1

for occupation in occupations_list:
offers_page = requests.get(occupation)
offers_soup = BeautifulSoup(offers_page.content, 'lxml')
offers = offers_soup.find('ul', class_='result-list list-unstyled')

这在我上面的html中得到一个标题

for job in offers:
try:
headline = job.find('h2', class_='t4 media-heading').text
except Exception as e:
pass
print(headline)

问题是，在几个标题已经被刮掉之后，我得到了以下错误消息:

TypeError                                 Traceback (most recent call last)
<ipython-input-77-cbf6b87ac0f9> in <module>()
3   offres_soup = BeautifulSoup(offres_page.content, 'lxml')
4   offres = offres_soup.find('ul', class_='result-list list-unstyled')
----> 5   for job in offres:
6     try:
7       headline = job.find('h2', class_='t4 media-heading').text
TypeError: 'NoneType' object is not iterable

Answer 1

None表示没有发现，您可以使用if…is None检查而不是尝试—除非没有发现，否则跳过，如下所示

for occupation in occupations_list:
offers_page = requests.get(occupation)
offers_soup = BeautifulSoup(offers_page.content, 'lxml')
offers = offers_soup.find('ul', class_='result-list list-unstyled')
if offers is None:
continue
print("Processing offers")

将print("Processing offers")替换为实际处理