python充电

flatten()函数的用法  使数组或者矩阵变成一维

用在数组

python">import numpy as np
a = [[1,3],[2,4],[3,5]]
a = np.array(a)
b = a.flatten()
print(a)
print(b)输出：
[[1 3][2 4][3 5]]
[1 3 2 4 3 5]Process finished with exit code 0

用在列表（不可以直接用在列表）

直接用会报错

import numpy as np
a = [[1,3],[2,4],[3,5]]
b = flatten(a)
print(a)
print(b)报错

用在矩阵：

import numpy as np
a = [[1,3],[2,4],[3,5]]
a = np.mat(a)
b = a.flatten()#矩阵
c = b.A#数组
print(a)
print(b)
print(c)输出：
[[1 3][2 4][3 5]]
[[1 3 2 4 3 5]]
[[1 3 2 4 3 5]]Process finished with exit code 0