How do I count the total number of words in a Pandas dataframe cell and add those to a new column?

Assuming that a sentence with n words has n-1 spaces in it, there's another solution:

df['new_column'] = df['count_column'].str.count(' ') + 1

This solution is probably faster, because it does not split each string into a list.

If count_column contains empty strings, the result needs to be adjusted (see comment below):

df['new_column'] = np.where(df['count_column'] == '', 0, df['new_column'])

Let's say you have a dataframe df that you've generated using

df = pandas.read_csv('dataset.csv')

You would then add a new column with the word count by doing the following:

df['new_column'] = df.columnToCount.apply(lambda x: len(str(x).split(' ')))

Keep in mind the space in the split is important since you're splitting on new words. You may want to remove punctuation or numbers and reduce to lowercase before performing this as well.

df = df.apply(lambda x: x.astype(str).str.lower())
df = df.replace('\d+', '', regex = True)
df = df.replace('[^\w\s\+]', '', regex = True)

For dataframe df remove punctuations from the selected column:

string_text = df['reviews'].str
df['reviews'] = string_text.translate(str.maketrans('', '', string.punctuation))

Get the word count:

df['review_word_count'] = df['reviews'].apply(word_tokenize).tolist()
df['review_word_count'] = df['review_word_count'].apply(len)

Write to a CSV with new column:

df.to_csv('./data/dataset.csv')

from collections import Counter

df['new_column'] = df['count_column'].apply(lambda x: Counter(" ".join(x).split(" ")).items())