列表推导式

a=[[1,2],[3,4],[5,6]]

x=[j for i in a for j in i ]

print(x)

import numpy as np
b=np.array(a).flatten().tolist()
print(b)

结果：

[1, 2, 3, 4, 5, 6]
[1, 2, 3, 4, 5, 6]