我正在做一些网页抓取，但我想出了一些我想不出来的东西。基本上，我需要检查ResultSet元素releaseDate的第0个元素是否包含[]

但是当“content”不在标记中时，我会得到一个错误，比如Traceback (most recent call last):

File "", line 1, in

File "imdbQuestion.py", line 18, in

if releaseDate[0]['content']:

File "build/bdist.macosx-10.8-intel/egg/bs4/element.py", line 879, in __getitem__

KeyError: 'content'

如何检查'content'是否在releaseDate中而不会导致错误？

另外，如何从ResultSet对象中提取所需的内容？

完整代码是：import requests

from bs4 import BeautifulSoup

file = codecs.open('imdb.txt', 'w', encoding = 'utf-8')

#iterate through last value

for increment in range(7,10):

imdbNum = '015008' + str(increment)

url = 'http://www.imdb.com/title/tt' + imdbNum

urlCode = requests.get(url)

soup = BeautifulSoup(urlCode.content)

#get release date

releaseDate = soup.findAll(attrs={'itemprop':'datePublished'})

abc = releaseDate

#error checking - assign '.' to releaseDate if releaseDate[0] is blank

#if not blank, check if 'content' is in releaseDate[0]. if so, we are good. if not, assign 'CHECK' to releaseDate[0]

if releaseDate:

if releaseDate[0]['content']:

releaseDate = releaseDate[0]['content']

else:

releaseDate = 'CHECK'

else:

releaseDate = '.'

print releaseDate

file.close()