This seems to be a simple question but I am struggling with errors from quite some time. Imagine an array
a = np.array([2,3,4,5,6])
I want to test which elements in the array belong to another list
[2,3,6]
If I do
a in [2,3,6]
Python raises "ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()"
In return, i would like to get a boolean array-like
array([ True, True, False, False, True], dtype=bool)
Use np.isin to create a boolean mask then use np.argwhere on this mask to find the indices of array elements that are non-zero:
m = np.isin(a, lst)
indices = np.argwhere(m)
# print(m)
array([ True, True, False, False, True])
# print(indices)
array([[0], [1], [4]])
import numpy as np
arr1 = np.array([2,3,4,5,6])
arr2 = np.array([2,3,6])
arr_result = [bool(a1 in arr2) for a1 in arr1]
print(arr_result)
I have used simple list-comprehension logic to do this.
Output:
[True,True,False,False,True]