Problems using snowballstemmer for a list of Turkish words in Python

I'm trying to use a library called snowballstemmer in Python, but it seems that it's not working as expected. What could the reason be? Please see my code below.

My data set:

df=[['musteri', 'hizmetlerine', 'cabuk', 'baglaniyorum'],['konuda', 'yardımcı', 'oluyorlar', 
   'islemlerimde']]

I have applied snowballstemmer package and import TurkishStemmer

  from snowballstemmer import TurkishStemmer
  turkStem=TurkishStemmer()
  data_words_nostops=[turkStem.stemWord(word) for word in df]
  data_words_nostops

  [['musteri', 'hizmetlerine', 'cabuk', 'baglaniyorum'],
   ['konuda', 'yardımcı', 'oluyorlar', 'islemlerimde']]

Unfortunately it didn't work. But when I applied it to single words, it works as expected:

 turkStem.stemWord("islemlerimde")
 'islem'

What could be the problem? Any help will be appreciated.

Thank you.

Solution

Did you mean to have a list of strings instead of a list of lists containing strings?

I was able to get the stems for each word when I reformatted your code this way:

from snowballstemmer import TurkishStemmer

df = [
    'musteri',
    'hizmetlerine',
    'cabuk',
    'baglaniyorum',
    'konuda',
    'yardımcı',
    'oluyorlar',
    'islemlerimde'
]
turkStem = TurkishStemmer()
data_words_nostops = [turkStem.stemWord(word) for word in df]
print(data_words_nostops)

If you have a list of lists of strings (lets say its what you've defined as df) and you want to flatten it down to a single list of words, you can do something like this:

df = [
    ['musteri', 'hizmetlerine', 'cabuk', 'baglaniyorum'],
    ['konuda', 'yardımcı', 'oluyorlar', 'islemlerimde']
]
flattened_df = [item for sublist in df for item in sublist]

# Output:
# ['musteri', 'hizmetlerine', 'cabuk', 'baglaniyorum', 'konuda', 'yardımcı', 'oluyorlar', 'islemlerimde']

Credit for the above goes to this StackOverflow post.

Alternatively, you could just correct the looping to address the problem with your original layout:

df = [
    ['musteri', 'hizmetlerine', 'cabuk', 'baglaniyorum'],
    ['konuda', 'yardımcı', 'oluyorlar', 'islemlerimde']
]
turkStem = TurkishStemmer()
all_stem_lists = []

for word_group in df:
    output_stems = []
    for word in word_group:
        stem = turkStem.stemWord(word)
        output_stems.append(stem)
    all_stem_lists.append(output_stems)

print(all_stem_lists)