what is the difference between ‘transform’ and ‘fit_transform’ in sklearn

Question

In scikit-learn estimator api,

fit() : used for generating learning model parameters from training data

transform() :
parameters generated from fit() method,applied upon model to generate transformed data set.

fit_transform() :
combination of fit() and transform() api on same data set

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Checkout Chapter-4 from this book & answer from stackexchange for more clarity