np.triu(m, k)，取矩阵a的上三角数据。斜线开始列位置由k确定
Signature: np.triu(m, k=0)
Docstring:
Upper triangle of an array.
Return a copy of an array with the elements below the k-th diagonal
zeroed.
Please refer to the documentation for tril for further details.
See Also
--------
tril : lower triangle of an array
Examples
np.triu([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], -1)
>>>array([[ 1, 2, 3],
[ 4, 5, 6],
[ 0, 8, 9],
[ 0, 0, 12]])
np.triu([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], 1)
>>>array([[0, 2, 3],
[0, 0, 6],
[0, 0, 0],
[0, 0, 0]])
np.triu([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], 0)
>>>array([[1, 2, 3],
[0, 5, 6],
[0, 0, 9],
[0, 0, 0]])
np.tirl()，取矩阵a的下三角数据
- 整理自网络