from sklearn.preprocessing import StandardScaler

The StandardScaler is a preprocessing module in the sklearn library of Python, which is used to standardize the data features by scaling them to a mean of 0 and a standard deviation of 1.

The StandardScaler module transforms the data in such a way that the mean of the data is zero and the standard deviation is one. This is an important step for many machine learning algorithms that use distance metrics, such as K-Nearest Neighbors, Support Vector Machines, and Principal Component Analysis.

Standardization is a common step in the preprocessing of data before feeding it into a machine learning algorithm, as it helps to ensure that each feature contributes equally to the analysis.

The StandardScaler can be used to transform both training and test data, and can be incorporated into a machine learning pipeline to automate the preprocessing step.