what is new with int conversion in Python 3

[Sayth Renshaw]

I am doing a passage in a book that was written for python 2 i am writing everything in 3.

This is the author Ivan Idris code to show time difference between python and numpy arrays. The only edit I made was to fix the print statements.

#!/usr/bin/env/python

import sys
from datetime import datetime
import numpy as np

"""
 This program demonstrates vector addition the Python way.
 Run from the command line as follows

  python vectorsum.py n

 where n is an integer that specifies the size of the vectors.

 The first vector to be added contains the squares of 0 up to n.
 The second vector contains the cubes of 0 up to n.
 The program prints the last 2 elements of the sum and the elapsed time.
"""

def numpysum(n):
   a = np.arange(n) ** 2
   b = np.arange(n) ** 3
   c = a + b

   return c

def pythonsum(n):
   a = range(n)
   b = range(n)
   c = []

   for i in range(len(a)):
       a[i] = i ** 2
       b[i] = i ** 3
       c.append(a[i] + b[i])

   return c

size = int(sys.argv[1])

start = datetime.now()
c = pythonsum(size)
delta = datetime.now() - start
print("The last 2 elements of the sum", c[-2:])
print("PythonSum elapsed time in microseconds", delta.microseconds)

start = datetime.now()
c = numpysum(size)
delta = datetime.now() - start
print("The last 2 elements of the sum", c[-2:])
print("NumPySum elapsed time in microseconds", delta.microseconds)


However when I run this I get a valuerror. So either something has changed with int or datetime I cannot google a consistent answer.


---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-8-a54a878f293d> in <module>()
     37    return c
     38 
---> 39 size = int(sys.argv[1])
     40 
     41 start = datetime.now()

ValueError: invalid literal for int() with base 10: '-f'

Had this before?

Sayth