具有AttributeError：“ tuple”对象的Python脚本没有属性“ lower”

Question

I'm kind of new to python. A python script has been running fine - it now dies with the following error:

File "/var/newspaper/myscript.py", line 495, in <listcomp>
    return sorted(set([x.lower() for x in self.regex.findall(text)] +
 self.regex_a.findall(text)))
AttributeError: 'tuple' object has no attribute 'lower'

The lines around the error are as follows:

def findall_unique(self, text):
    """
    Find all unique occurrences of keywords in text.
    """
    # Ordinary words are being lower(), abbreviations are returned as is
    return sorted(set([x.lower() for x in self.regex.findall(text)] + self.regex_a.findall(text)))

def get_related_ids(self, words):
    result = set(self.related_ids.get(x.lower()) for x in words)
    result = [x for x in result if x is not None]
    result.sort()
    return result

I guess a check is needed to see if x has an attribute lower before attempting to do the set/sorted operations... if it does that return is ok, if not then something else has to be done... can you suggest some code that will fix the error?

Answer 1

That should work:

[x.lower() for y in self.regex.findall(text) for x in y]

y is a tuple, and this lowers all elements of the tuple.

The docs for re.findall say: "If one or more groups are present in the pattern, return a list of groups; this will be a list of tuples if the pattern has more than one group." This is where the list of tuples comes from. Groups here means that you have parentheses in your regexp that define matching groups.