Python 正则表达式 AttributeError: 'NoneType' 对象没有属性 'group'

Python regex AttributeError: 'NoneType' object has no attribute 'group'

提问by Winterflags

I use Regex to retrieve certain content from a search box on a webpage with selenium.webDriver.

我使用正则表达式从网页上的搜索框中检索某些内容selenium.webDriver。

searchbox = driver.find_element_by_class_name("searchbox")
searchbox_result = re.match(r"^.*(?=(\())", searchbox).group()

The code works as long as the search box returns results that match the Regex. But if the search box replies with the string "No results"I get error:

只要搜索框返回与正则表达式匹配的结果，代码就可以工作。但是如果搜索框回复字符串"No results"我得到错误：

AttributeError: 'NoneType' object has no attribute 'group'

AttributeError: 'NoneType' 对象没有属性 'group'

How can I make the script handle the "No results"situation?

我怎样才能让脚本处理这种"No results"情况？

采纳答案by Winterflags

I managed to figure out this solution, it had to do with neglecting group()for the situation where the searchbox reply is "No results"and thus doesn't match the Regex.

我设法找出了这个解决方案，它与忽略group()搜索框回复"No results"因此与正则表达式不匹配的情况有关。

try:
    searchbox_result = re.match("^.*(?=(\())", searchbox.group()
except AttributeError:
    searchbox_result = re.match("^.*(?=(\())", searchbox)

or simply:

或者干脆：

try:
    searchbox_result = re.match("^.*(?=(\())", searchbox.group()
except:
    searchbox_result = None

回答by Maroun

When you do

当你做

re.match("^.*(?=(\())", search_result.text)

then if no match was found, Nonewill be returned:

然后如果没有找到匹配项，None将返回：

Return Noneif the string does not match the pattern; note that this is different from a zero-length match.

None如果字符串与模式不匹配，则返回；请注意，这与零长度匹配不同。

You should check that you got a result before you apply groupon it:

在申请之前，您应该检查是否获得了结果group：

res = re.match("^.*(?=(\())", search_result.text)
if res:
    # ...