[R] find a sequence of characters in a vector

[Sundar Dorai-Raj]

use gregexpr and paste

> aze <- paste(c("a", "z", "e"), collapse = "")
> sequence <- paste(c("a","z","e","r","t","a","z","a","z","e","c"), collapse = "")
> gregexpr(aze, sequence, fixed = TRUE)
[[1]]
[1] 1 8
attr(,"match.length")
[1] 3 3

HTH,

--sundar

On Fri, Jun 5, 2009 at 6:22 AM, Ptit_Bleu<ptit_bleu at yahoo.fr> wrote:
>
> Hello,
>
> I'm just looking for an easy way to find the positions of a complete
> sequence in a bigger vector.
> For example :
> c("a","z","e") in c("a","z","e","r","t","a","z","a","z","e","c")
> and the result should be
> 1 8
> that is the positions of the beginning of the complete sequence.
>
> I tried with %in%, match, is.element but all I get is, for example
> which(c("a","z","e") in c("a","z","e","r","t","a","z","a","z","e","c"))
> 1 2 3
> meaning that each character is in the bigger vector.
>
> It must be easy, except for me. Sorry.
>
> If you have a solution, thanks in advance to share it.
> Have a good week-end,
> Ptit Bleu.
>
> --
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