How to get all 2D diagonals of a 3D NumPy array?
Last Updated :
02 Sep, 2020
Let’s see the program for getting all 2D diagonals of a 3D NumPy array. So, for this we are using numpy.diagonal() function of NumPy library. This function return specified diagonals from an n-dimensional array.
Syntax: numpy.diagonal(a, axis1, axis2)
Parameters:
- a: represents array from which diagonals has to be taken
- axis1: represents first axis to be taken for 2-d subarray
- axis2: represents second axis to be taken for 2-d subarray
Return: array of diagonal elements.
Now, let’s see an example:
Example 1:
Python3
import numpy as np
arr = np.arange( 3 * 4 * 4 ).reshape( 3 , 4 , 4 )
print ( "Original 3d array:\n" ,
arr)
diag_arr = np.diagonal(arr,
axis1 = 1 ,
axis2 = 2 )
print ( "2d diagonal array:\n" ,
diag_arr)
|
Output:
Original 3d array:
[[[ 0 1 2 3]
[ 4 5 6 7]
[ 8 9 10 11]
[12 13 14 15]]
[[16 17 18 19]
[20 21 22 23]
[24 25 26 27]
[28 29 30 31]]
[[32 33 34 35]
[36 37 38 39]
[40 41 42 43]
[44 45 46 47]]]
2d diagonal array:
[[ 0 5 10 15]
[16 21 26 31]
[32 37 42 47]]
Example 2:
Python3
import numpy as np
arr = np.arange( 3 * 3 * 4 ).reshape( 3 , 3 , 4 )
print ( "Original 3d array:\n" ,
arr)
diag_arr = np.diagonal(arr,
axis1 = 1 ,
axis2 = 2 )
print ( "2d diagonal array:\n" ,
diag_arr)
|
Output:
Original 3d array:
[[[ 0 1 2 3]
[ 4 5 6 7]
[ 8 9 10 11]]
[[12 13 14 15]
[16 17 18 19]
[20 21 22 23]]
[[24 25 26 27]
[28 29 30 31]
[32 33 34 35]]]
2d diagonal array:
[[ 0 5 10]
[12 17 22]
[24 29 34]]
Example 3:
Python3
import numpy as np
arr = np.arange( 3 * 5 * 6 ).reshape( 3 , 5 , 6 )
print ( "Original 3d array:\n" ,
arr)
diag_arr = np.diagonal(arr,
axis1 = 1 ,
axis2 = 2 )
print ( "2d diagonal array:\n" ,
diag_arr)
|
Output:
Original 3d array:
[[[ 0 1 2 3 4 5]
[ 6 7 8 9 10 11]
[12 13 14 15 16 17]
[18 19 20 21 22 23]
[24 25 26 27 28 29]]
[[30 31 32 33 34 35]
[36 37 38 39 40 41]
[42 43 44 45 46 47]
[48 49 50 51 52 53]
[54 55 56 57 58 59]]
[[60 61 62 63 64 65]
[66 67 68 69 70 71]
[72 73 74 75 76 77]
[78 79 80 81 82 83]
[84 85 86 87 88 89]]]
2d diagonal array:
[[ 0 7 14 21 28]
[30 37 44 51 58]
[60 67 74 81 88]]
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