iCrazybest
iCrazybest
Programming language:Python
2021-07-22 09:33:27
0
Q:

The function scale provides a quick and easy way to perform

aes
aes
Code: Python
2021-07-27 04:52:24 
# Standardization

from sklearn import preprocessing
import numpy as np
X_train = np.array([[1., -1., 2.],
                    [2., 0., 0.],
                    [0., 1., -1.]])
X_scaled = preprocessing.scale(X_train)

X_scaled
# array([[ 0.  ..., -1.22...,  1.33...],
#        [ 1.22...,  0.  ..., -0.26...],
#        [-1.22...,  1.22..., -1.06...]])

# Scaled data has zero mean and unit variance:

X_scaled.mea(axis=0)
# array([0., 0., 0.])
X_scaled.std(axis=0)
# array([1., 1., 1.])

scaler = preprocessing.StandardScaler().fit(X_train)
scaler
# StandardScaler()

scaler.mean_
# array([1. ..., 0. ..., 0.33...])

scaler.scale_
# array([0.81..., 0.81..., 1.24...])

scaler.transform(X_train)
array([[ 0.  ..., -1.22...,  1.33...],
       [ 1.22...,  0.  ..., -0.26...],
       [-1.22...,  1.22..., -1.06...]])

X_test = [[-1., 1., 0.]]
scaler.transform(X_test)
# array([[-2.44...,  1.22..., -0.26...]])
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