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# Return the Upper triangle of an array and zero elements just above the main diagonal in Numpy

To return the upper triangle of an array, use the **numpy.triu()** method in Python Numpy −

- The 1st parameter is the input array
- The 2nd parameter is the 'k' i.e. the diagonal above which to zero elements.

Here, k = 0 (the default) is the main diagonal, k < 0 is below it and k > 0 is above.' Array. The k = 2 value is to zero elements just above the main diagonal.

The function returns a copy of an array with the elements below the k-th diagonal zeroed. For arrays with ndim exceeding 2, triu will apply to the final two axes.

## Steps

At first, import the required library −

import numpy as np

Create a 2d array −

arr = np.array([[36, 36, 78, 88], [92, 81, 98, 45], [22, 67, 54, 69 ], [69, 80, 80, 99]])

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)

Return the upper triangle of an array using the numpy.triu() method in Python Numpy. The 2nd parameter is the 'k' i.e. the diagonal above which to zero elements. The k = 2 value is to zero elements just above the main diagonal −

print("\nResult...\n",np.triu(arr, k = 2))

## Example

import numpy as np # Create a 2d array arr = np.array([[36, 36, 78, 88], [92, 81, 98, 45], [22, 67, 54, 69 ], [69, 80, 80, 99]]) # 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) # To return the upper triangle of an array, use the numpy.triu() method in Python Numpy # The 1st parameter is the input array # The 2nd parameter is the 'k' i.e. the diagonal above which to zero elements. # k = 0 (the default) is the main diagonal, k < 0 is below it and k > 0 is above.' array # The k = 2 value is to zero elements just above the main diagonal print("\nResult...\n",np.triu(arr, k = 2))

## Output

Array... [[36 36 78 88] [92 81 98 45] [22 67 54 69] [69 80 80 99]] Array datatype... int64 Array Dimensions... 2 Our Array Shape... (4, 4) Elements in the Array... 16 Result... [[ 0 0 78 88] [ 0 0 0 45] [ 0 0 0 0] [ 0 0 0 0]]

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