str1 = 'abacad'
print(str1.rindex('a'))
Output ：
4
str1.rindex(‘a’) return str1 The first one found from the back to the front ‘a’ The subscript .
But no lindex, Because from left to right is index, No need to add l.
and , The list doesn't have rindex, Maybe it's because it's used less .
