numpy.tri#

numpy.tri(N, M=None, k=0, dtype=<class 'float'>, *, like=None)[源代码]#

An array with ones at and below the given diagonal and zeros elsewhere.

Parameters:

Nint: Number of rows in the array.
Mint, optional: Number of columns in the array. By default, M is taken equal to N.
kint, optional: The sub-diagonal at and below which the array is filled. k = 0 is the main diagonal, while k < 0 is below it, and k > 0 is above. The default is 0.
dtypedtype, optional: Data type of the returned array. The default is float.
likearray_like, optional: Reference object to allow the creation of arrays which are not NumPy arrays. If an array-like passed in as like supports the __array_function__ protocol, the result will be defined by it. In this case, it ensures the creation of an array object compatible with that passed in via this argument.

在 1.20.0 版本加入.

Returns:

trindarray of shape (N, M): Array with its lower triangle filled with ones and zero elsewhere; in other words T[i,j] == 1 for j <= i + k, 0 otherwise.

Examples

>>> import numpy as np
>>> np.tri(3, 5, 2, dtype=np.int_)
array([[1, 1, 1, 0, 0],
       [1, 1, 1, 1, 0],
       [1, 1, 1, 1, 1]])

>>> np.tri(3, 5, -1)
array([[0.,  0.,  0.,  0.,  0.],
       [1.,  0.,  0.,  0.,  0.],
       [1.,  1.,  0.,  0.,  0.]])