美丽汤中的这个错误意味着什么？

Question

我正在使用 PyQt4 和 BeautifulSoup 编写小脚本。基本上，您指定 url 和脚本，以便从网页下载所有图片。

在输出中，当我提供http://yahoo.com时，它会下载除一张之外的所有图片：

...
Download Complete
Download Complete
File name is wrong 
Traceback (most recent call last):
  File "./picture_downloader.py", line 41, in loadComplete
    self.download_image()
  File "./picture_downloader.py", line 58, in download_image
    print 'File name is wrong ',image['src']
  File "/usr/local/lib/python2.7/dist-packages/beautifulsoup4-4.1.3-py2.7.egg/bs4/element.py", line 879, in __getitem__
    return self.attrs[key]
KeyError: 'src'

http://stackoverflow.com的输出是：

Download Complete
File name is wrong  h
Download Complete

最后，这是代码的一部分：

# SLOT for loadFinished
def loadComplete(self): 
    self.download_image()

def download_image(self):
    html = unicode(self.frame.toHtml()).encode('utf-8')
    soup = bs(html)

    for image in soup.findAll('img'):
        try:
            file_name = image['src'].split('/')[-1]
            cur_path = os.path.abspath(os.curdir)
            if not os.path.exists(os.path.join(cur_path, 'images/')):
                os.makedirs(os.path.join(cur_path, 'images/'))
            f_path = os.path.join(cur_path, 'images/%s' % file_name)
            urlretrieve(image['src'], f_path)
            print "Download Complete"
        except:
            print 'File name is wrong ',image['src']
    print "No more pictures on the page"

Answer 1

这意味着该image元素没有属性"src"，并且您会收到相同的错误两次：一次是file_name = image['src'].split('/')[-1]在 except 块中，一次是在 except 块中'File name is wrong ',image['src']。

避免该问题的最简单方法是替换soup.findAll('img')为soup.findAll('img',{"src":True})，这样它只会找到具有属性的元素src。

如果有两种可能性，请尝试以下操作：

for image in soup.findAll('img'):
    v = image.get('src', image.get('dfr-src'))  # get's "src", else "dfr_src"
                                                # if both are missing - None
    if v is None:
        continue  # continue loop with the next image
    # do your stuff