How to Fix TypeError: only integer scalar arrays can be converted to a scalar index with 1D numpy indices array

To fix the TypeError: only integer scalar arrays can be converted to a scalar index with 1D numpy indices array error in Python, you can use the .astype(int) function to convert the object dtype array to an int dtype array.

The TypeError: only integer scalar arrays can be converted to a scalar index with 1D numpy indices array error occurs when you try to use a non-scalar NumPy array as an index to access elements of another NumPy array. The indexing operation expects integer scalar values or integer scalar arrays, but the provided index is not in the expected format.

Here’s an example that causes the error:

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
index = np.array([1, 2], dtype=object)

result = arr[index]

print(result)

Output

TypeError: only integer scalar arrays can be converted to a scalar index

In this example, the index array has an object dtype. When used as an index to access elements of the arr array, it raises the “TypeError: only integer scalar arrays can be converted to a scalar index” error.

To fix this error, you can convert the object dtype array to an int dtype array using the .astype(int) function:

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
index = np.array([1, 2], dtype=object)

index = index.astype(int)
result = arr[index]

print(result)

Output

[2 3]

Now the code accesses the elements at the specified indices correctly without raising the error.

That’s it.