TypeError: 'NoneType' object is not subscriptable

[matsujju]

I am having issue with the code you shared on Medium article named "A Practitioner's Guide to Natural Language Processing (Part I) — Processing & Understanding Text" where contraction.py file was used in the code.

def expand_contractions(text, contraction_mapping=CONTRACTION_MAP):
    
    contractions_pattern = re.compile('({})'.format('|'.join(contraction_mapping.keys())), 
                                      flags=re.IGNORECASE|re.DOTALL)
    def expand_match(contraction):
        match = contraction.group(0)
        first_char = match[0]
        expanded_contraction = contraction_mapping.get(match)\
                                if contraction_mapping.get(match)\
                                else contraction_mapping.get(match.lower())                       
        expanded_contraction = first_char+expanded_contraction[1:]
        return expanded_contraction
        
    expanded_text = contractions_pattern.sub(expand_match, text)
    expanded_text = re.sub("'", "", expanded_text)
    return expanded_text

and while running the function on the data I am getting the error as mentioned in title.

df['Text_of_quest'] = [expand_contractions(x) for x in df['Text_of_quest'].to_list() if x is not None]

Traceback:

TypeError                                 Traceback (most recent call last)
<ipython-input-23-4358bc968219> in <module>
----> 1 get_ipython().run_cell_magic('timeit', '', "df['Text_of_quest'] = [expand_contractions(x) for x in df['Text_of_quest'].to_list() if x is not None]\n")

~/.conda/envs/project1/lib/python3.8/site-packages/IPython/core/interactiveshell.py in run_cell_magic(self, magic_name, line, cell)
   2360             with self.builtin_trap:
   2361                 args = (magic_arg_s, cell)
-> 2362                 result = fn(*args, **kwargs)
   2363             return result
   2364 

<decorator-gen-60> in timeit(self, line, cell, local_ns)

~/.conda/envs/project1/lib/python3.8/site-packages/IPython/core/magic.py in <lambda>(f, *a, **k)
    185     # but it's overkill for just that one bit of state.
    186     def magic_deco(arg):
--> 187         call = lambda f, *a, **k: f(*a, **k)
    188 
    189         if callable(arg):

~/.conda/envs/project1/lib/python3.8/site-packages/IPython/core/magics/execution.py in timeit(self, line, cell, local_ns)
   1158             for index in range(0, 10):
   1159                 number = 10 ** index
-> 1160                 time_number = timer.timeit(number)
   1161                 if time_number >= 0.2:
   1162                     break

~/.conda/envs/project1/lib/python3.8/site-packages/IPython/core/magics/execution.py in timeit(self, number)
    167         gc.disable()
    168         try:
--> 169             timing = self.inner(it, self.timer)
    170         finally:
    171             if gcold:

<magic-timeit> in inner(_it, _timer)

<magic-timeit> in <listcomp>(.0)

<ipython-input-9-90eb3c3afe2e> in expand_contractions(text, contraction_mapping)
     12         return expanded_contraction
     13 
---> 14     expanded_text = contractions_pattern.sub(expand_match, text)
     15     expanded_text = re.sub("'", "", expanded_text)
     16     return expanded_text

<ipython-input-9-90eb3c3afe2e> in expand_match(contraction)
      9                                 if contraction_mapping.get(match)\
     10                                 else contraction_mapping.get(match.lower())
---> 11         expanded_contraction = first_char+expanded_contraction[1:]
     12         return expanded_contraction
     13 

TypeError: 'NoneType' object is not subscriptable

Why NoneType error even after i checked for None value in my dataframe column?

[linehammer]

The error is self-explanatory. You are trying to index None. You can not, because 'NoneType' object is not subscriptable. This means that you tried to do:

None[something]

In general, the error means that you attempted to index an object that doesn't have that functionality. You might have noticed that the method sort() that only modify the list have no return value printed – they return the default None. This is a design principle for all mutable data structures in Python.