19 lines
565 B
Python
19 lines
565 B
Python
import numpy as np
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import pandas as pd
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a = np.array([1,2])
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b = a.reshape(1,2)
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# b = np.mat(a)
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c = np.array([[1,2],[1,3],[1,4]])
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# d = c.reshape(3,2)
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d = np.mat(c)
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print(f"a is {a} {a.shape} shape {a.shape[0]}, b is {b} {b.shape} shape {b.shape[0],b.shape[1]}, "
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f"c is {c} {c.shape}, d is {d} {d.shape}")
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# 注意 e = np.mat([[2],[1],[3]]) 是错误的
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# 矩阵与矩阵相乘， 矩阵与数组相乘完全不同
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e = np.array([[2],[1],[3]])
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print(f"c*e is {c*e}\n")
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f = np.mat([[2],[1]])
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print(f" c shape is {c}, and f shape is {f} \n"
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f"c*f ",c*f) |