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

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

The Python "TypeError: only integer scalar arrays can be converted to a scalar index" occurs when array indexing is used on a list instead of a NumPy array. The solution is to convert the list into a NumPy array. It can also occur when two NumPy matrices are concatenated using the wrong syntax. The solution is to input the two matrics as a tuple.

This error will occur if you use array indexing on a list intead of a NumPy array. The following is an example of when this error occurs.

import numpy as np

example_list = list(range(20000))

# ⛔️ TypeError: only integer scalar arrays can be converted to a scalar index
output = example_list[indices.astype(int)]

To solve this error, convert example_list, a list object, into a NumPy array object.

import numpy as np

example_list = list(range(20000))

# ✅ this runs
output = np.array(example_list)[indices.astype(int)]

This error will occur if you concatenate two NumPy matrices using the wrong syntax. Here is an example of when this occurs.

import numpy as np

#👇️ create a 2 x 2 matrix that looks like:
# [[1., 0.]
#  [0., 1.]]
matrix = np.eye(2)

# ⛔️ TypeError: only integer scalar arrays can be converted to a scalar index
np.concatenate(a, a)

# ✅ this runs
np.concatenate((a, a))
>> array([[1., 0.],
          [0., 1.],
          [1., 0.],
          [0., 1.]])

The correct solution is to input the two matrices a tuple.

Conclusion

The Python "TypeError: only integer scalar arrays can be converted to a scalar index" occurs when array indexing is used on a list instead of a NumPy array. The solution is to convert the list into a NumPy array. It can also occur when two NumPy matrices are concatenated using the wrong syntax. The solution is to input the two matrics as a tuple.