/python_programming

Code from my studies in programming using python

Primary LanguagePython

Head First - Programming with Python

Cap. 2

import urllib.request # library urllib.request
import time # library time
price = 99.99
while price > 4.74:

    time.sleep(900)
    page = urllib.request.urlopen("http://beans.itcarlow.ie/prices-loyalty.html") # library.function()
    text = page.read().decode("utf8")
    where = text.find(">$")
    start_price = where + 2
    end_price = start_price + 4
    price = float(text[start_price:end_price])

print("Buy!", time_read)

Programming Toolbox

  • Strings are sequences of individuals characters
  • The characters of an string are identified by the index
  • The values of the index are “deslocamentos” which start on ZERO
  • The methods gives variables with built in functionalities
  • The programming libraries provide an predefined collection of codes and functions
  • The variables has types (float, char,…)
  • Number is type of data
  • Strings are type of data

Python Toolbox

  • s[4] access the 5th character of the variable “s” and it is an string
  • s[b:12] access an substring inside the string “s” (until, but no inclusive)
  • the method s.find( ) to search strings
  • the method s.upper( ) for the conversion strings to UPPERCASE
  • float( ) convert string to numbers with decimals
  • the library urllib.request is used to communication with urls
  • the library time is used to work with data