#1
#2
str1='http://www.jianshu.com/u/31a09b9ab717'
print(str1.split('/')[4])
#3
s="abcdefg"
print(s[3])
print(s[2:4])
print(s[:5])
print(s[3:])
print(s[::-1])
print(s[::2])
#4
list1= [1,2,3,4,5,6,7]
print(list1[3])
print(list1[2:4])
print(list1[:5])
print(list1[3:])
print(list1[::-1])
print(list1[::2])
#5
touple1=(1,2,3,4,5,6,7)
print(touple1[3])
print(touple1[2:4])
print(touple1[:5])
print(touple1[3:])
print(touple1[::-1])
print(touple1[::2])
