Fancy indexing with a list of indices in python

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                              It is one of the advanced indexing methods in Numpy. It makes you to find arbitrary elements in the list or array of index. Let us implement in different ways.

  • ·       1D array
  • ·       Reordering the elements of 1D array
  • ·       2D array
  • ·       Selecting specific elements

👉1D array:

              This deals with Single dimensional array. First, it reads the array elements. Find the arbitrary elements. Finally, print the output.

Code:

import numpy as np1

s_arr = np1.array([11, 22, 33, 44, 55, 66, 77])

indices = [0, 2, 4]

result = s_arr[indices]

print("The indices are:",result)

Output:

The indices are: [11 33 55]

👉Reordering the elements of 1D array:

              It Rearranges the indices in this program.

Code:

import numpy as np1

s_arr = np1.array([11, 22, 33, 44, 55, 66, 77])

print("The Rearrangement of indices are:",s_arr[[4, 2, 0]])

Output:

The Rearrangement of indices are: [55 33 11]

👉2D array:

              This program creates a 2D array with elements. It selects a set of rows. Finally, it displays the output.

Code:

import numpy as np1

s_arr = np1.array([

    [1, 2],

    [4, 3],

    [5, 6],

    [8, 7]

])

rows = [0, 1, 3]

print("Here , is the fancy indices:\n",s_arr[rows])

Output:

Here , is the fancy indices:

 [[1 2]

 [4 3]

 [8 7]]

👉Selecting specific elements in 2D array:

              This program selects the specific elements from the array.

Code:

import numpy as np1

s_arr = np1.array([

    [11, 22, 33],

    [44, 55, 66],

    [77, 88, 99]

])

print("This is the selection of specific elements:\n",s_arr[[0, 1, 2], [2, 1, 0]])

Output:

This is the selection of specific elements:

 [33 55 77]

These are the various methods to find fancy indices in python using numpy. Hope, you understood the concept. Keep Coding!!!

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