In this chapter, we acquired the fundamental concepts of NLP as an important subfield in machine learning, including tokenization, stemming and lemmatization, and PoS tagging. We also explored three powerful NLP packages and realized some common tasks using NLTK and spaCy. Then, we continued with the main project exploring newsgroups data. We started with extracting features with tokenization techniques and went through text preprocessing, stop words removal, and stemming and lemmatization. We then performed dimensionality reduction and visualization with t-SNE and proved that count vectorization is a good representation for text data.

We had some fun mining the newsgroups data using dimensionality reduction as an unsupervised approach. Moving forward in the next chapter, we'll be continuing our unsupervised learning journey, specifically on topic modeling and clustering.