#!/usr/bin/env python3
tag = '<a href="http://www.python.org">Python web site</a>'
print(tag[9:30])  # http://www.python.org
print(tag[32:-4])  # Python web site
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print(numbers[3:6])  # [4, 5, 6]
print(numbers[0:1])  # [1]
print(numbers[7:10])  # [8,9,10]
print(numbers[-3:-1])  # [8,9]
print(numbers[-3:0])  # []
print(numbers[-3:])  # [8,9,10]
print(numbers[:3])  # [1,2,3]
print(numbers[:])  # [1,2,3,4,5,6,7,8,9,10]
print(numbers[0:10:1])  # [1,2,3,4,5,6,7,8,9,10]
print(numbers[0:10:2])  # [1,3,5,7,9]
print(numbers[3:6:3])  # [4]
print(numbers[::4])  # [1,5,9]
# 步长为负数时,列表的排序方式改变为倒序
print(numbers[8:3:-1])  # [9, 8, 7, 6, 5]
print(numbers[10:0:-2])  # [10, 8, 6, 4, 2]
print(numbers[0:10:-2])  # []
print(numbers[::-2])  # [10, 8, 6, 4, 2]
print(numbers[5::-2])  # [ 6, 4, 2]
print(numbers[:5:-2])  # [ 10,8]
# 从类似于http://www.something.com的URL中提取域名
# url = input('Please enter the URL:')
# domain = url[11:-4]
# print("Domain name:"+domain)