I have a string vector like these:
[1] "1-1-1" "1-1-2" "1-2-1"

And I wanna replace the second "-" with "0", that is, I wanna get the result
like: [1] "1-101" "1-102" "1-201".

How should I write the Regular Expressions? Thanks!

-- 
뼝휠뱍
Department of Sociology
Fudan University

	[[alternative HTML version deleted]]

