Python: AttributeError: 'NoneType' object has no attribute 'rfind'

Question

I am trying to determine the file extension using os.path.splitext

here is my code:

for emailid in msgs:
    typ, s = mail.fetch(emailid, "(RFC822)")
    m = email.message_from_string(s[0][1])
    result = re.findall(pattern,str)
    if result:     
        for part in m.walk():
            filename = part.get_filename()
            if filename:
                extension = os.path.splitext(fileName)
                if extension[1][1:] == 'csv':      
                    ### Process into a dataframe
                    df = pd.read_csv(StringIO(filename))

here is the error readout from IPython:

#### Begin error Message #####

    AttributeError                            Traceback (most recent call last)
<ipython-input-83-71fabd157c43> in <module>()
     40             if filename:
     41                 print type(filename)
---> 42                 extension = os.path.splitext(fileName)
     43                 if extension[1][1:] == 'csv':
     44                     ### Process into a dataframe

C:\Anaconda2\lib\ntpath.pyc in splitext(p)
    198 
    199 def splitext(p):
--> 200     return genericpath._splitext(p, sep, altsep, extsep)
    201 splitext.__doc__ = genericpath._splitext.__doc__
    202 

C:\Anaconda2\lib\genericpath.pyc in _splitext(p, sep, altsep, extsep)
     97     leading dots.  Returns "(root, ext)"; ext may be empty."""
     98 
---> 99     sepIndex = p.rfind(sep)
    100     if altsep:
    101         altsepIndex = p.rfind(altsep)

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

#### End Error message #####

NoneType should mean I am not passing anything, when I print type(filename) i get:

how do I pass the file so I can determine extension and then create a dataframe? do I need to save to disk

this will be for a parsing script that gets regularly scheduled csv'ed emailed to it, hence the regex to determine which rule to follow.

Answer 1

In extension = os.path.splitext(fileName) , you're using the variable fileName , instead of filename . Python is case-sensitive, so these are different variables. Evidently, fileName is elsewhere set to None, and changing that instance to filename should fix this error.