[R] Regex: workaround for variable length negative lookbehind

[Wacek Kusnierczyk]

Gabor Grothendieck wrote:
> Try this:
>
>   
>> vec <- c("aaaa", "baaa", "bbaa", "bbba", "baamm", "aa")
>>     
>
>   
>> grep("^(?!(.)\\1{1,}$).*(.)\\2{1,}$", vec, perl = TRUE)
>>     

or even

grep("^(?!(.)\\1+$).*(.)\\2+$", vec, perl = TRUE)


vQ