Stop 10 · NLP & Modern AIProjects · 1/1

Sentiment Analysis Project

Part of the Data Science Roadmap

In short

Brands read thousands of reviews and tweets a day. Build a model that sorts them into happy and unhappy, compare a classic baseline with a transformer, and you have a strong NLP project.

The practice project for this phase — build a text classifier that predicts sentiment (positive/negative/neutral), comparing a classic approach (TF-IDF + logistic regression) against a modern one (pretrained model).

The mascot sorts feedback cards into two trays, one with a smiling face and one with a frowning face.

Think of it like this

Sorting the feedback cards

A restaurant owner reads every feedback card at closing time and drops it in a happy or unhappy tray. With ten cards that's fine. With ten thousand a day, they need help. Your model is the helper, and you check it on cards it hasn't seen.

Watch it happen

Project build plan

Get data
Clean
Baseline
Transformer
Demo

1/5Use a labelled public dataset like IMDB, or app reviews with star ratings turned into labels.

The big ideas

What you need to know

Check balance

If 90% of reviews are positive, accuracy misleads. Report per-class F1.

Baseline vs transformer

Show both. A small gain at ten times the cost is a real trade-off worth discussing.

Sarcasm and mixed reviews

'Great, another late delivery' fools many models. Collect such errors and discuss them.

Hinglish is hard

Mixed Hindi-English text breaks English-only models. Mention it as a limitation or a stretch goal.

See it in code

Walk through the code

python
1from datasets import load_dataset2from sklearn.feature_extraction.text import TfidfVectorizer3from sklearn.linear_model import LogisticRegression4from sklearn.metrics import classification_report5from sklearn.pipeline import make_pipeline6 7data = load_dataset("imdb")8train, test = data["train"], data["test"]9 10clf = make_pipeline(TfidfVectorizer(ngram_range=(1, 2), min_df=2), LogisticRegression(max_iter=1000))11clf.fit(train["text"], train["label"])12print(classification_report(test["label"], clf.predict(test["text"])))

1/3Load the labelled IMDB reviews from Hugging Face Datasets.

The baseline every sentiment project needs. 25,000 training reviews fit in well under a few minutes on a laptop.

Save yourself the pain

Common mistakes

Oops

Reporting only the transformer's score with no baseline.

Do this instead

Always show a simple baseline so readers can judge whether the heavy model was worth it.

Oops

Testing on reviews the model saw while you tuned it.

Do this instead

Keep a test set aside from the start and use it once at the end.

Your mission

First milestone: baseline and error list

~40 min

Quick check

Why use ngram_range=(1, 2) in the TF-IDF baseline?

Go deeper

  1. 1Find a public sentiment-labeled dataset (product reviews, tweets, etc).
  2. 2Build both a classic baseline and a pretrained-model-based approach, and compare accuracy.
  3. 3Write up which approach you'd recommend for production, and why (accuracy vs simplicity vs cost).

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