你好,我有这个矩阵
例如
import numpy as np
a= np.arange(9).reshape(3, 3)
[[1. 2. 3. ]
[4. 5. 6. ]
[7. 8. 9. ]]
如何删除所选列(例如 col = 1)的最后一个值,其余上方的值会被推下,如果有空格,则将其替换为“0”。
因此矩阵变为:
[[1. 0. 3. ]
[4. 2. 6. ]
[7. 5. 9. ]]
将第二列滚动,然后将该列的第一个元素设置为零。
a = np.arange(1,10).reshape(3, 3)
a[:, 1] = np.roll(a[:, 1], 1)
a[0, 1] = 0
print(a)
输出:
[[1 0 3]
[4 2 6]
[7 5 9]]
np.pad
:>>> import numpy as np
>>> a= np.arange(1, 10).reshape(3, 3)
>>> print a
[[1 2 3]
[4 5 6]
[7 8 9]]
>>> a[:,1] = np.pad(a[:,1], pad_width=1, mode='constant')[:a.shape[1]]
>>> print a
[[1 0 3]
[4 2 6]
[7 5 9]]
In [215]: a = np.arange(1,10).reshape(3,3)
In [216]: temp = np.zeros(a.shape[0],a.dtype)
In [217]: temp[1:] = a[:-1,1]
a
中:In [218]: a[:,1] = temp
In [219]: a
Out[219]:
array([[1, 0, 3],
[4, 2, 6],
[7, 5, 9]])