减去没有循环的数组中的行

Question

How can I subtract two rows in python numpy ? without using loops

for example:

import numpy as np
x = np.array([[2.2, 3.4, 5.2], [1., 5.4, 5.]])

# expected result:
y = [[-1.2, 2., -0.2]]

Answer 1

You can do the following:

import numpy as np
x = np.array([[2.2, 3.4, 5.2], [1., 5.4, 5.]])
np.diff(x.T)
# array([[-1.2],
#    [ 2. ],
#    [-0.2]])

Answer 2

Try subtracting with subtraction:

import numpy as np
x = np.array([[2.2, 3.4, 5.2], [1., 5.4, 5.]])
print(x[1] - x[0])