[R] Derive pattern from vector

[Petr Savicky]

On Sat, Feb 11, 2012 at 09:11:12AM -0800, syrvn wrote:
> Hello,
> 
> consider the following vector 'chars':
> 
> 
> chars <- c(A, B, C, C, D, E, E, E, F, F, F)
> 
> 
> I need to convert 'chars' into the following pattern:
> 
> 
> 1, 2, 3, 3, 4, 5, 5, 5, 6, 7, 8
> 
> As soon as there are duplicates they get the same number otherwise it's
> increasing numbers.
> 
> However, for the char 'F' it should be always increasing numbers. Is that
> possible in R?
> 
> 
> I used the following code:
> 
> 
> chars <- c('A', 'B', 'C', 'C', 'D', 'E', 'E', 'E', 'F', 'F', 'F')
> 		
> chars_dup <- duplicated(chars)
> 		
> cumsum(!chars_dup)
> 
>  [1] 1 2 3 3 4 5 5 5 6 6 6
> 
> 
> But I do not know how to treat 'F' in the way described above.

Try this

  non_dup <- !duplicated(chars) | chars == 'F'
  cumsum(non_dup)
   [1] 1 2 3 3 4 5 5 5 6 7 8

HTH.

Petr Savicky.