Estimator basics

scikit-learn estimators are fitted to data using the fit() method.

Transformers & pre-processors

Typical workflows have multiple steps, often a data pre-processing step and a final predictor.

Pipelines: chaining pre-processors & estimators

Model Evaluation

Fitting a model does not guarantee good predictions on unknown data. Below: 5-fold cross validation example.

Automatic parameter searches

Estimator effectiveness usually depends on a few key variables. It's usually not clear what parameter values are optimal. scikit-learn provides tools to auto-search for optimal values.