title: "Set routines" date: 2026-05-24T13:51:04Z

Set routines

1import numpy as np

1np.__version__

'1.11.2'

1author = 'kyubyong. longinglove@nate.com'

Making proper sets

Q1. Get unique elements and reconstruction indices from x. And reconstruct x.

1x = np.array([1, 2, 6, 4, 2, 3, 2])

unique elements = [1 2 3 4 6]
reconstruction indices = [0 1 4 3 1 2 1]
reconstructed = [1 2 6 4 2 3 2]

Boolean operations

Q2. Create a boolean array of the same shape as x. If each element of x is present in y, the result will be True, otherwise False.

1x = np.array([0, 1, 2, 5, 0])
2y = np.array([0, 1])

[ True  True False False  True]

Q3. Find the unique intersection of x and y.

1x = np.array([0, 1, 2, 5, 0])
2y = np.array([0, 1, 4])

[0 1]

Q4. Find the unique elements of x that are not present in y.

1x = np.array([0, 1, 2, 5, 0])
2y = np.array([0, 1, 4])

[2 5]

Q5. Find the xor elements of x and y.

1x = np.array([0, 1, 2, 5, 0])
2y = np.array([0, 1, 4])

[2 4 5]

Q6. Find the union of x and y.

1x = np.array([0, 1, 2, 5, 0])
2y = np.array([0, 1, 4])

[0 1 2 4 5]