字符串与正则表达式匹配

Question

I am trying to write a regular expression in Python which takes a string and checks if:

1. The last character is a vowel.
2. The last 2 characters are not the same.

This is what I came up with:

[aeiou]$

Can anybody help me with point number 2: last 2 characters are not the same. For example, expresso is valid and expressoo is not valid.

Answer 1

It might be easier to do this without a regular expression.

eg if s[-2]!=s[-1] and s[-1] in 'aeiou'

Answer 2

(?i)([aeiouy])(?!\1)[aeiouy]$

EDIT:

This is also appealing for not having a repeat:

(?i)(?=[aeiouy]{2}$)(.)(?!\1).

Answer 3

我所能做的最好：

r"\w*(?:[^a\W]a|[^e\W]e|[^i\W]i|[^u\W]u|[^o\W]o)\b"