Prevent strings being truncated when replacing values in a numpy array

Question

Lets say I have arrays a and b

a = np.array([1,2,3])
b = np.array([\'red\',\'red\',\'red\'])

If I were to apply s

Answer 1

You can handle variable length strings by setting the dtype of b to be "object":

import numpy as np
a = np.array([1,2,3])
b = np.array(['red','red','red'], dtype="object")

b[a<3] = "blue"

print(b)

this outputs:

['blue' 'blue' 'red']

This dtype will handle strings, or other general Python objects. This also necessarily means that under the hood you'll have a numpy array of pointers, so don't expect the performance you get when using a primitive datatype.