check if numpy array is subset of another array

Question

Similar questions have already been asked on SO, but they have more specific constraints and their answers don\'t apply to my question.

Generally speaking, what is t

Answer 1

You can do this easily via iterating over an array in list comprehension. A toy example is as follows:

import numpy as np
x = np.arange(30).reshape(10,3)
searchKey = [4,5,8]
x[[0,3,7],:] = searchKey
x

gives

 array([[ 4,  5,  8],
        [ 3,  4,  5],
        [ 6,  7,  8],
        [ 4,  5,  8],
        [12, 13, 14],
        [15, 16, 17],
        [18, 19, 20],
        [ 4,  5,  8],
        [24, 25, 26],
        [27, 28, 29]])

Now iterate over the elements:

ismember = [row==searchKey for row in x.tolist()]

The result is

[True, False, False, True, False, False, False, True, False, False]

You can modify it for being a subset as in your question:

searchKey = [2,4,10,5,8,9]  # Add more elements for testing
setSearchKey = set(searchKey)
ismember = [setSearchKey.issuperset(row) for row in x.tolist()]

If you need the indices, then use

np.where(ismember)[0]

It gives

array([0, 3, 7])