Glossary · Phase 3 · Machine learning

Estimator

Also written: estimators

scikit-learn's name for anything with a fit method: models, scalers and whole pipelines.

An estimator is anything that learns from data. It always learns with the same button, fit. You give it the inputs, called X. For most models you also give it the answers, called y. Here X is the table of features and y is the column you want to predict, such as whether a customer left.
From the lesson The scikit-learn workflow

Try it now

Every scikit-learn project follows this shape. Fit and predict look the same for every model.

Learn it properly

The scikit-learn workflow · Fit, predict and evaluate with the standard ML library. About 35 minutes.

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Other terms from the same lesson

ColumnTransformer: A scikit-learn step that prepares different columns in different ways, such as scaling numbers and one-hot encoding categories.
data drift: When the data a model sees in use slowly stops looking like the data it learned from, so its accuracy quietly falls.
scikit-learn: A popular Python library of ready-made machine-learning models and tools.

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