numpy.triu#

numpy.triu(m, k=0)[source]#

Upper triangle of an array.

Return a copy of an array with the elements below the k-th diagonal zeroed. For arrays with ndim exceeding 2, triu will apply to the final two axes.

Please refer to the documentation for tril for further details.

See also

tril: lower triangle of an array

Examples

>>> import numpy as np
>>> 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(np.arange(3*4*5).reshape(3, 4, 5))
array([[[ 0,  1,  2,  3,  4],
        [ 0,  6,  7,  8,  9],
        [ 0,  0, 12, 13, 14],
        [ 0,  0,  0, 18, 19]],
       [[20, 21, 22, 23, 24],
        [ 0, 26, 27, 28, 29],
        [ 0,  0, 32, 33, 34],
        [ 0,  0,  0, 38, 39]],
       [[40, 41, 42, 43, 44],
        [ 0, 46, 47, 48, 49],
        [ 0,  0, 52, 53, 54],
        [ 0,  0,  0, 58, 59]]])