《Head First Programming》---python 3_函数

import urllib.request
import time

def get_price():

page = urllib.request.urlopen("http://www.laofengxiang.com/index.php")
text = page.read().decode("utf8")
#print(text)
where = text.find("铂金: ")
#print(where)
start_of_price = where + 4;
#print(start_of_price)
end_of_price = start_of_price + 3
#print(end_of_price)
#print(text[start_of_price:end_of_price])
return (text[start_of_price:end_of_price])

price_now = input("Do you want to see the price now (Y/N) ? ")
if price_now == "Y":
print(get_price())
else:
price = float(get_price())
while price > 499.9:
time.sleep(3600) #每隔1小时刷新一次
price = float(get_price())
print("Price is ", price, "元/克")
print("Buy for my lover!")