# convert keywords in one column into several dummy columns

My dataframe has some free text fields named: {'title', 'description', 'location'}

I prepared this text column by: concatenating all into a new column, dropping numbers, dropping words less than 3 char, etc...

As final step in preparing, I removed Stop Words. So, probably at this moment the column only contains relevant keywords.

How can I convert these keywords sentences (several words per row, as space separated words, in just one string column) into dummy columns and get the 0-1 values when, per row, this column contains the keyword?

I was checking the CountVectorizer object, but I couldn't find any use case like this one. So, it is probably not the proper tool to use...

Let's say that your dataframe is called df and the column with your preprocessed text as text.

What you want to do, as you already thought, is to apply a CountVectorizer.

import numpy as np
from sklearn.feature_extraction.text import CountVectorizer
import pandas as pd

count = CountVectorizer(binary = True)
bow = count.fit_transform(df['text'].values)

pd.DataFrame(bow.toarray(), columns = count.get_feature_names())


If you remove the binary parameter from the CountVectorizer you will get the actual frequency of the keyword and not just the appearance with 0-1.

• thanks Tasos, the binary parameter was the point i've missed. – Cristian C. Bittel Oct 4 '19 at 22:06