Numpy的基本运算

# 类比数据库的增删改查 C U R D
import numpy as np
data1 = np.array([1,2,3,4,5])
print(data1)
data2 = np.array([[1, 2],
                 [3, 4]])
print(data2)
print(data1.shape)
print(data2.shape)

# zero  ones
print(np.zeros([2, 3]), np.ones([2, 2]))

print('一维数组1:', (np.zeros((5, 4, 3), np.uint8)))

# 改查
data2[1, 0] = 5
print(data2)
print(data2[1,1])

# 基本运算
data3 = np.ones([2, 3])
print(data3 * 2)
print(data3 / 3)
print(data3 + 2)
# 矩阵加乘
data4 = np.array([[1,2,3], [4,5,6]])
print(data3 + data4)
print(data3 * data4)

结果如下：

image.png

不等维矩阵相加

import numpy as np
# 不等维的矩阵加法
x = np.array([[1, 2], [3, 4], [5, 6]])
# 等效 
b = np.array([1, 1])
b2 = np.array([[1, 1], [1, 1], [1, 1]])
print(x + b)
print(x + b2)

结果一致:

image.png