Numpy_广播

实现不同维度的 a+b

方法1：

import numpy as np
a = np.array([[1, 2, 3],
             [4, 5, 6],
             [11, 21, 13],
             [4, 5, 6]])

b = np.array([1, 2, 3])

for i in range(4):
    a[i, :] += b
print(a)

方法2：

import numpy as np
a = np.array([[1, 2, 3],
             [4, 5, 6],
             [11, 21, 13],
             [4, 5, 6]])
b = np.array([1, 2, 3])

print(a + np.tile(b, (4, 1)))

方法3(广播)：

import numpy as np
a = np.array([[1, 2, 3],
              [4, 5, 6],
              [11, 21, 13],
              [4, 5, 6]])
b = np.array([1, 2, 3])

print(a + b)

结果相同：

[[ 2  4  6]
 [ 5  7  9]
 [12 23 16]
 [ 5  7  9]]