numpy.tri

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

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.

New in version 1.20.0.

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

>>> np.tri(3, 5, 2, dtype=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.]])