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 the numpy package import numpy as np # Create 3D-numpy array # of 4 rows and 4 columns arr = np.arange(3 * 4 * 4).reshape(3, 4, 4) print("Original 3d array:\n", arr) # Create 2D diagonal array 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 the numpy package import numpy as np # Create 3D numpy array # of 3 rows and 4 columns arr = np.arange(3 * 3 * 4).reshape(3, 3, 4) print("Original 3d array:\n", arr) # Create 2D diagonal array 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 the numpy package import numpy as np # Create 3D numpy array # of 5 rows and 6 columns arr = np.arange(3 * 5 * 6).reshape(3, 5, 6) print("Original 3d array:\n", arr) # Create 2D diagonal array 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]]
