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概念介绍:
将数据按期属性(按列进行)减去其均值,并除以其标准差。得到的结果是,对于每个属性/每列来说所有数据都聚集在0附近,方差为1。
代码示例:
- import numpy as np
- from sklearn.preprocessing import MinMaxScaler,StandardScaler
-
- def autoNorm(dataset):
- x = dataset[:, 0:1]
- ##method2 Z-socre by Skit-Learn
- std = StandardScaler()
- x_std = std.fit_transform(x)
- print(x_std[2])
-
- ##method2 Z-socre by formula
- print(np.average(x))
- print(np.std(x))
- print((x[2]-np.mean(x))/np.std(x))
-
- if __name__ == '__main__':
- returnMat, classLabelVector=file2matrix('F:\\datingTestSet2.txt')
- autoNorm(returnMat)
执行结果:
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