Python error when calling NumPy from class method with map

Question

The following code throws me the error:

Traceback (most recent call last):
  File \"\", line 25, in 
    sol = anna.main()
  File \"\", line 17, in         


        

Answer 1

Plain Python

Actually, you need neither numpy nor math because sqrt(x) is x**0.5. So:

sqrt(x**5) = x ** (5/2) = x ** 2.5

It means you could replace your code with:

class anaconda():
    def __init__(self):
        self.mice = range(10000)

    def eat(self, food):
        calc = food ** 2.5
        return calc

    def main(self):
        sol = list(map(self.eat, self.mice))
        return sol


if __name__ == '__main__':
    anna = anaconda()
    sol = anna.main()
    print(len(sol))

NumPy

If you want to use NumPy, you can enjoy the fact that you can work with arrays as if they were scalars:

import numpy as np

class anaconda():

    def __init__(self):
        self.mice = np.arange(10000)

    def eat(self, food):
        return food ** 2.5

    def main(self):
        return self.eat(self.mice)


if __name__ == '__main__':
    anna = anaconda()
    sol = anna.main()
    print(len(sol))

Short refactor

Removing all the unneeded object-oriented-with-weird-names, your code becomes:

import numpy as np
print(np.arange(10000) ** 2.5)