numpy.tril#
- numpy.tril(m, k=0)[source]#
Lower triangle of an array.
Return a copy of an array with elements above the k-th diagonal zeroed. For arrays with
ndim
exceeding 2,tril
will apply to the final two axes.- Parameters:
- marray_like, shape (…, M, N)
Input array.
- kint, optional
Diagonal above which to zero elements. k = 0 (the default) is the main diagonal, k < 0 is below it and k > 0 is above.
- Returns:
- trilndarray, shape (…, M, N)
Lower triangle of m, of same shape and data-type as m.
See also
triu
same thing, only for the upper triangle
Examples
>>> import numpy as np >>> np.tril([[1,2,3],[4,5,6],[7,8,9],[10,11,12]], -1) array([[ 0, 0, 0], [ 4, 0, 0], [ 7, 8, 0], [10, 11, 12]])
>>> np.tril(np.arange(3*4*5).reshape(3, 4, 5)) array([[[ 0, 0, 0, 0, 0], [ 5, 6, 0, 0, 0], [10, 11, 12, 0, 0], [15, 16, 17, 18, 0]], [[20, 0, 0, 0, 0], [25, 26, 0, 0, 0], [30, 31, 32, 0, 0], [35, 36, 37, 38, 0]], [[40, 0, 0, 0, 0], [45, 46, 0, 0, 0], [50, 51, 52, 0, 0], [55, 56, 57, 58, 0]]])