Question

I’m trying to learn python. I am using 3.1.2 and the o’reilly book is using 3.0.1
here is my code:

import urllib.request

price = (99.99)

while price > 4.74:
    page = urllib.request.urlopen ("http://www.beans-r-us.biz/prices-loyalty.html")
    text = page.read().decode("utf8")

    where = text.find('>$')

    start_of_price = where + 2
    end_of_price = start_of_price + 6

    price = float(text[start_of_price:end_of_price])

print ("Buy!")

Here is my error:

Traceback (most recent call last):
  File "/Users/odin/Desktop/Coffe.py", line 14, in <module>
    price = float(text[start_of_price:end_of_price])
ValueError: invalid literal for float(): 4.59</
>>> 

What is wrong?

Answer 1

You are calculating end_of_price as start_of_price + 6. Actually your price value seems to be only 4 characters long, so that you also include the two characters following in the string you want to convert to a float. Python then complains that 4.59</ is not a number.

If you instead set end_of_price to start_of_price + 4 it should work.