Question

我有一个从文件加载的数据集-

np.array([(5.1, 3.5, 1.4, 0.2, 'Iris-setosa'),
          (4.9, 3., 1.4, 0.2, 'Iris-setosa'),
          (4.7, 3.2, 1.3, 0.2, 'Iris-setosa'),
          (4.6, 3.1, 1.5, 0.2, 'Iris-setosa'),
          (5., 3.6, 1.4, 0.2, 'Iris-setosa')])

如何获取前4列的矩阵-

np.array([[5.1, 3.5, 1.4, 0.2],
          [4.9, 3., 1.4, 0.2],
          [4.7, 3.2, 1.3, 0.2],
          [4.6, 3.1, 1.5, 0.2],
          [5., 3.6, 1.4, 0.2]])

并将标签放入另一个数组-

np.array(['Iris-setosa', 'Iris-setosa', 'Iris-setosa', 'Iris-setosa',
          'Iris-setosa'])

Answer 1

import pandas as pd

data=np.array([(5.1, 3.5, 1.4, 0.2, 'Iris-setosa') ,
 (4.9, 3. , 1.4, 0.2, 'Iris-setosa'),
 (4.7, 3.2, 1.3, 0.2, 'Iris-setosa'),
 (4.6, 3.1, 1.5, 0.2, 'Iris-setosa'),
 (5. , 3.6, 1.4, 0.2, 'Iris-setosa')])

df= pd.DataFrame(data)
first4col = df.iloc[:,0:3]
tags=df.iloc[:,4]

将set的ndArray转换为矩阵

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