[R] Recode numbers

[Dennis Murphy]

Hi:

Here's another option:

rep(b, rle(a)$lengths)

> identical(a1, rep(b, rle(a)$lengths))
[1] TRUE

rle(a)$lengths computes a table of the number of consecutive repeats
of a number (or run lengths). It will have the same length as b in
this case. Using rep() with the table of lengths as repetitions gets
the desired result:

> rep(b, rle(a)$lengths)
 [1]  1  5  8  8  9  9 14 20  3 10 10 12  6 16  7 11 13 13 17 18  2  4 15 19

HTH,
Dennis

On Wed, Jun 1, 2011 at 10:19 AM, Lisa <lisajca at gmail.com> wrote:
> Dear all,
>
> I have two sets of numbers that look like
>
> a <- c(1, 2, 3, 3, 4, 4, 5, 6, 1, 2, 2, 3, 1, 2, 1, 2, 3, 3, 4, 5, 1, 2, 3,
> 4)
>
> b <- c(1, 5, 8, 9, 14, 20, 3, 10, 12, 6, 16, 7, 11, 13, 17, 18, 2, 4, 15,
> 19)
>
> I just want to use “b” to encode “a” so that “a” looks like
>
> a1<- c(1, 5, 8, 8, 9, 9, 14, 20, 3, 10, 10, 12, 6, 16, 7, 11, 13, 13, 17,
> 18, 2, 4, 15, 19)
>
> Does anyone have a suggestion how to deal with this? Thank you in advance.
>
> Lisa
>
>
> --
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