What is feature engineering and why is it important?

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Ravi Vishwakarma · Answer

Feature engineering is the process of creating, transforming, or selecting input variables (features) that help a machine learning model perform better.
What does it involve?
Creating new features
Example: From a “date of birth” column, you can create an “age” feature.
Transforming features
Example: Log-transforming skewed data to make it more normal.
Encoding categorical variables
Example: Converting “country” names into one-hot encoded vectors.
Handling missing values
Filling with mean/median or adding flags for missingness.
Scaling/normalizing features
To make features comparable, especially important in distance-based algorithms.
and 
Why is it important?
Improves model accuracy
Better features = more useful signals for the model to learn from.Reduces overfitting
Simplifying or encoding data properly can help the model generalize.Makes models interpretable
Cleaner and more meaningful features make the model’s decisions easier to understand.Compensates for limitations of algorithms
Some algorithms don't handle categorical or missing data well — feature engineering bridges that gap.
Real-World Example:
Suppose you're building a model to predict house prices.
Raw features:
Date: "2020-04-01"Size: 1500 sqftZip Code: 90210
Engineered features:
Age of house = Current Year − Built YearIs weekend sale? = Based on dateOne-hot encoded location from zip code
These engineered features give your model richer context than the raw data alone.

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What is feature engineering and why is it important?

Ravi Vishwakarma

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What does it involve?

Why is it important?

Real-World Example:

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