How to make create a triangle of "1"?-CodePudding

I want to create this:

1 0 0 0 0 0
1 1 0 0 0 0
1 1 1 0 0 0
1 1 1 1 0 0
1 1 1 1 1 0
1 1 1 1 1 1

However, I prefer if a library is used to create this, how do I go about doing this?

Note: NumPy can be used to create the array as well.

There are a lot of answers on SO, but they all provide answers that do not use libraries, and I haven't been able to find anything online to produce this!

CodePudding user response：

You can use np.tril:

>>> np.tril(np.ones((6, 6), dtype=int))
array([[1, 0, 0, 0, 0, 0],
       [1, 1, 0, 0, 0, 0],
       [1, 1, 1, 0, 0, 0],
       [1, 1, 1, 1, 0, 0],
       [1, 1, 1, 1, 1, 0],
       [1, 1, 1, 1, 1, 1]])

CodePudding user response：

Using `numpy.tri`

Syntax:

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

Basically it creates an array with 1's at and below the given diagonal and 0's elsewhere.

Example:

import numpy as np
np.tri(6, dtype=int)

>>>
array([[1, 0, 0, 0, 0, 0],
       [1, 1, 0, 0, 0, 0],
       [1, 1, 1, 0, 0, 0],
       [1, 1, 1, 1, 0, 0],
       [1, 1, 1, 1, 1, 0],
       [1, 1, 1, 1, 1, 1]])

Using numpy.tri

Using `numpy.tri`