1、矩阵

定义矩阵：
a = [[1,2,3],
[2,3,4]]

2、数组

定义数组：
import numpy as np
a = np.array([[1,2,3],
[2,3,4]])

3、sum()

sum( a ):
（1）如果a是矩阵：
1）一维矩阵：
a = [1,2,3] print(‘sum(a) = ‘, sum(a))
输出：sum(a) = 6
2）二维矩阵：
b= [[1,2,3], [2,3,4]] print(‘sum(b) = ‘, sum(b))
会报错：TypeError: unsupported operand type(s) for +: ‘int’ and ‘list’

（2）如果b是数组：
1）一维数组：
import numpy as np c = np.array([1,2,3]) print(‘sum(c) = ‘, sum(c))
输出：sum(c) = 6
2）二维数组：
import numpy as np d = np.array([[1,2,3], [2,3,4]]) print(‘sum(d) = ‘, sum(d))
输出：sum(b) = [3 5 7]

4、np.sum() {import numpy as np}

np.sum( a ):
（1）如果a是矩阵：
1）一维矩阵：
e = [1,2,3] print(‘np.sum(e) = ‘, np.sum(e))
输出：np.sum(e) = 6
2）二维矩阵：
f= [[1,2,3], [2,3,4]] print(‘np.sum(f) = ‘, np.sum(f))
输出：np.sum(f) = 15

（2）如果b是数组：
1）一维数组：
import numpy as np g = np.array([1,2,3]) print(‘np.sum(g) = ‘, np.sum(g))
输出：np.sum(g) = 6
2）二维数组：
import numpy as np h = np.array([[1,2,3], [2,3,4]]) print(‘np.sum(h) = ‘, np.sum(h))
输出：np.sum(h) = 15