Além do saco de palavras

Bag-of-words and TF-IDF get you a solid first model. But at some point the score stops climbing, and you need richer features to push past it.

Word counts ignore everything about a document except which words appear. Tone, length, and structure all carry signal that pure counts throw away.

How long a text is can predict its label. Spam is often short, while detailed reviews run long, so length becomes a useful feature.

Lots of exclamation marks or question marks hint at emotion or urgency. Counting punctuation turns that hidden cue into a number.

SHOUTING in all caps often signals spam or anger. The ratio of uppercase letters is a tiny but surprisingly powerful feature.

How hard a text is to read can separate audiences and styles. A readability score boils sentence and word complexity into one handy number.

Author, timestamp, and source often sit right next to your text. This metadata can predict labels without reading a single word.

Unique words divided by total words measures how varied a text is. Repetitive writing scores low, and that diversity ratio can help your model.

Every idea here ends as a number you can hand to a model. A good feature simply turns intuition about text into measurable values.

The best features come from knowing your problem. If you understand what separates the classes, you can design a feature that captures it. 💡

Begin with bag-of-words, then layer in a few hand-built features. Measure each one so you keep only the additions that truly help.

Why go beyond plain bag-of-words features?

Counts miss tone, length, and structure. Hand-built features like length, punctuation, and readability turn those cues into numbers that lift your model. ✅