# Create an array with ones at and below the given diagonal and zeros elsewhere with a different output type in Numpy

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To create an array with ones at and below the given diagonal and zeros elsewhere, use the numpy.tri() method in Python Numpy

• The 1st parameter is the number of rows in the array
• The 2nd parameter is the number of columns in the array
• The "type" parameter is used to set the type of the returned array

The tri() function returns an array with its lower triangle filled with ones and zero elsewhere; in other words T[i,j] == 1 for j <= i + k, 0 otherwise.

## Steps

At first, import the required library −

import numpy as np

Now, create an array with ones at and below the given diagonal and zeros elsewhere, using the numpy.tri() method −

arr = np.tri(3, 5, dtype = int)

Displaying our array −

print("Array...\n",arr)

Get the datatype −

print("\nArray datatype...\n",arr.dtype)


Get the dimensions of the Array −

print("\nArray Dimensions...\n",arr.ndim)

Get the shape of the Array −

print("\nOur Array Shape...\n",arr.shape)

Get the number of elements of the Array −

print("\nElements in the Array...\n",arr.size)

## Example

import numpy as np

# To create an array with ones at and below the given diagonal and zeros elsewhere, use the numpy.tri() method in Python Numpy
# The 1st parameter is the number of rows in the array
# The 2nd parameter is the number of columns in the array
# The "type" parameter is used to set the type of the returned array
arr = np.tri(3, 5, dtype = int)

# Displaying our array
print("Array...\n",arr)

# Get the datatype
print("\nArray datatype...\n",arr.dtype)

# Get the dimensions of the Array
print("\nArray Dimensions...\n",arr.ndim)

# Get the shape of the Array
print("\nOur Array Shape...\n",arr.shape)

# Get the number of elements of the Array
print("\nElements in the Array...\n",arr.size)

## Output

Array...
[[1 0 0 0 0]
[1 1 0 0 0]
[1 1 1 0 0]]

Array datatype...
int64

Array Dimensions...
2

Our Array Shape...
(3, 5)

Elements in the Array...
15