NumPy types with underscore: `int_`, `float_`, etc

Question

What is the significance of the underscore suffixing in int_, float_, etc.?

Answer 1

If you're unsure if your variable is scalar, list, or array, using the ones with "_" will ensure your code will work regardless (if that's the behavior you intended). See the example code below.

import numpy as np
scalar = 3
L1 = [3]
L2 = [1, 2, 3]

np.float(scalar)  # okay
np.float(L1)  # breaks (TypeError)
np.float(L2)  # breaks (TypeError)

np.float_(scalar)  # okay
np.float_(L1)  # okay
np.float_(L2)  # okay