Sven E. Templer sven.templer at gmail.com
Fri Sep 26 00:28:23 CEST 2014

```see inline for another vectorized example.

On 25 September 2014 23:05, David L Carlson <dcarlson at tamu.edu> wrote:
> Another approach
>
> fun <- function(i, dat=x) {
>      grp <- rep(1:(nrow(dat)/i), each=i)
>      aggregate(dat[1:length(grp),]~grp, FUN=sum)
> }
>
> lapply(2:6, fun, dat=TT)
>
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Rui Barradas
> Sent: Thursday, September 25, 2014 3:34 PM
> To: eliza botto; r-help at r-project.org
> Subject: Re: [R] adding rows
>
> Hello,
>
> Try the following.
>
> fun <- function(x, r){
>         if(r > 0){
>                 m <- length(x) %/% r
>                 y <- numeric(m)
>                 for(i in seq_len(m)){
>                         y[i] <- sum(x[((i - 1)*r + 1):(i*r)])
>                 }
>                 y
>         }else{
>                 NULL
>         }
> }

fun <- function(x,r) {
i <- length(x)%/%r
tapply(x[1:(i*r)], gl(i,r), sum)
}

>
> apply(TT, 2, fun, r = 2)
> apply(TT, 2, fun, r = 3)
> etc
>
>
> Hope this helps,
>
>
>
> Em 25-09-2014 20:50, eliza botto escreveu:
>> Dear useRs,
>> Here is my data with two columns and 20 rows.
>>> dput(TT)
>> structure(c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264, 288, 312, 336, 360, 384, 408, 432, 456, 480), .Dim = c(20L, 2L), .Dimnames = list(NULL, c("", "SS")))
>> I first of all want to sum up continuously  two rows (1 & 2, 3 & 4, 5 & 6 and so on) of each column.
>> Then I want to sum up 3 rows as (1-2-3,4-5-6,..... 16-17-18) and since 19th and 20th rows do not up 3 rows, so they should be ignored.
>> Similarly with 4 sets of rows and 5 sets of rows and even 6.
>> I hope I was clear.
>> Thankyou so very much in advance,
>> Eliza
>>       [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help