R help - Jul 2008 - sequential sum of a vector...

Hi R,

 

Let,

 

x=1:80

 

I want to sum up first 8 elements of x, then again next 8 elements of x,
then again another 8 elements..... So, my new vector should look like: 

c(36,100,164,228,292,356,420,484,548,612)

 

I used:

 

aggregate(x,list(rep(1:10,each=8)),sum)[-1]

or

rowsum(x,group=rep(1:10,each=8))

 

 

But without grouping, can I achieve the required? Any other ways of
doing this?

 

Thanks, Shubha

 

This e-mail may contain confidential and/or privileged i...{{dropped:13}}

Dear Shubha,

Try this:

x=1:80
tapply(x,rep(1:10,each=8),sum)
 1   2   3   4   5   6   7   8   9  10
 36 100 164 228 292 356 420 484 548 612

HTH,

Jorge


On Wed, Jul 23, 2008 at 10:03 AM, Shubha Vishwanath Karanth <
shubhak@ambaresearch.com> wrote:
> Hi R,
>
>
>
> Let,
>
>
>
> x=1:80
>
>
>
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like:
>
> c(36,100,164,228,292,356,420,484,548,612)
>
>
>
> I used:
>
>
>
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
>
> or
>
> rowsum(x,group=rep(1:10,each=8))
>
>
>
>
>
> But without grouping, can I achieve the required? Any other ways of
> doing this?
>
>
>
> Thanks, Shubha
>
>
>
> This e-mail may contain confidential and/or privileged i...{{dropped:13}}
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

try this

colSums(matrix(x,8))

regards,

PF


+-------------------------------------------------
| Patrizio Frederic
| Research associate in Statistics,
| Department of Economics,
| University of Modena and Reggio Emilia,
| Via Berengario 51,
| 41100 Modena, Italy
|
| tel:  +39 059 205 6727
| fax:  +39 059 205 6947
| mail: patrizio.frederic at unimore.it
+-------------------------------------------------


2008/7/23 Shubha Vishwanath Karanth <shubhak at
ambaresearch.com>:
> Hi R,
>
>
>
> Let,
>
>
>
> x=1:80
>
>
>
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like:
>
> c(36,100,164,228,292,356,420,484,548,612)
>
>
>
> I used:
>
>
>
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
>
> or
>
> rowsum(x,group=rep(1:10,each=8))
>
>
>
>
>
> But without grouping, can I achieve the required? Any other ways of
> doing this?
>
>
>
> Thanks, Shubha
>
>
>
> This e-mail may contain confidential and/or privileged i...{{dropped:13}}
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Many Thanks Jorge... That was one more way...Is it possible if I can do
this without using rep(1:10,each=8) or the grouping....because I feel
the number 8 here is fixed... If there is some technique of tracking the
position of first 8, then next 8... don't know whether I am clear in
conveying... 

 

Thanks, shubha

 

________________________________

From: Jorge Ivan Velez [mailto:jorgeivanvelez@gmail.com] 
Sent: Wednesday, July 23, 2008 8:59 PM
To: Shubha Vishwanath Karanth
Cc: r-help@stat.math.ethz.ch
Subject: Re: [R] sequential sum of a vector...




Dear Shubha,

Try this:

x=1:80
tapply(x,rep(1:10,each=8),sum)
 1   2   3   4   5   6   7   8   9  10 
 36 100 164 228 292 356 420 484 548 612 

HTH,

Jorge



On Wed, Jul 23, 2008 at 10:03 AM, Shubha Vishwanath Karanth
<shubhak@ambaresearch.com> wrote:

Hi R,



Let,



x=1:80



I want to sum up first 8 elements of x, then again next 8 elements of x,
then again another 8 elements..... So, my new vector should look like:

c(36,100,164,228,292,356,420,484,548,612)



I used:



aggregate(x,list(rep(1:10,each=8)),sum)[-1]

or

rowsum(x,group=rep(1:10,each=8))





But without grouping, can I achieve the required? Any other ways of
doing this?



Thanks, Shubha



This e-mail may contain confidential and/or privileged
i...{{dropped:13}}

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.



This e-mail may contain confidential and/or privileged i...{{dropped:13}}

At 7:33 PM +0530 7/23/08, Shubha Vishwanath Karanth
wrote:
>Hi R,
>Let,
>x=1:80
>I want to sum up first 8 elements of x, then again next 8 elements of x,
>then again another 8 elements..... So, my new vector should look like:
>
>c(36,100,164,228,292,356,420,484,548,612)
>I used:
>aggregate(x,list(rep(1:10,each=8)),sum)[-1]
>or
>rowsum(x,group=rep(1:10,each=8))
>But without grouping, can I achieve the required? Any other ways of
>doing this?
>
>Thanks, Shubha
>
colSums(matrix(x,nrow=8))

Bill

-- 
William Revelle		http://personality-project.org/revelle.html
Professor			http://personality-project.org/personality.html
Department of Psychology             http://www.wcas.northwestern.edu/psych/
Northwestern University	http://www.northwestern.edu/
Attend  ISSID/ARP:2009               http://issid.org/issid.2009/

On Wed, Jul 23, 2008 at 4:03 PM, Shubha Vishwanath Karanth
<shubhak at ambaresearch.com> wrote:
> Hi R,
>
>
>
> Let,
>
>
>
> x=1:80
>
>
>
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like:
>
> c(36,100,164,228,292,356,420,484,548,612)
>
>
>
> I used:
>
>
>
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
>
> or
>
> rowsum(x,group=rep(1:10,each=8))
>
>
>
>
>
> But without grouping, can I achieve the required? Any other ways of
> doing this?
>
>
>
> Thanks, Shubha
>
>

How about

x<-1:80
filter(x,rep(1,8),"convolution",sides=1)[seq(8,length(x),by=8)]
##or
cumsum(x)[seq(8,length(x),by=8)]

?

/Gustaf


-- 
Gustaf Rydevik, M.Sci.
tel: +46(0)703 051 451
address:Essingetorget 40,112 66 Stockholm, SE
skype:gustaf_rydevik

on 07/23/2008 09:03 AM Shubha Vishwanath Karanth wrote:
> Hi R,
> 
>  
> 
> Let,
> 
>  
> 
> x=1:80
> 
>  
> 
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like: 
> 
> c(36,100,164,228,292,356,420,484,548,612)
> 
>  
> 
> I used:
> 
>  
> 
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
> 
> or
> 
> rowsum(x,group=rep(1:10,each=8))
> 
>  
> 
>  
> 
> But without grouping, can I achieve the required? Any other ways of
> doing this?
> 
>  
> 
> Thanks, Shubha

x <- 1:80

 > colSums(matrix(x, ncol = 10))
  [1]  36 100 164 228 292 356 420 484 548 612

If the original vector 'x' can be coerced to a rectangular matrix, you 
can create the matrix such that each column is a group:

 > matrix(x, ncol = 10)
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,]    1    9   17   25   33   41   49   57   65    73
[2,]    2   10   18   26   34   42   50   58   66    74
[3,]    3   11   19   27   35   43   51   59   67    75
[4,]    4   12   20   28   36   44   52   60   68    76
[5,]    5   13   21   29   37   45   53   61   69    77
[6,]    6   14   22   30   38   46   54   62   70    78
[7,]    7   15   23   31   39   47   55   63   71    79
[8,]    8   16   24   32   40   48   56   64   72    80


Then just get the sums of each column. Note that by default, the matrix 
is formed by columns. This can be adjusted using the 'byrow' argument to
matrix(). See ?matrix

HTH,

Marc Schwartz

> x=1:80
> 
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like: 
> 
> c(36,100,164,228,292,356,420,484,548,612)
> 
> I used:
> 
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
> 
> or
> 
> rowsum(x,group=rep(1:10,each=8))
> 
> But without grouping, can I achieve the required? Any other ways of
> doing this?
This works:
colSums(matrix(x, nrow=8))

I'm not sure if you benefit over using the methods you described though.

Regards,
Richie.

Mathematical Sciences Unit
HSL


------------------------------------------------------------------------
ATTENTION:

This message contains privileged and confidential inform...{{dropped:20}}

Maybe:

tapply(x, gl(10, 8), sum)

or

unlist(lapply(split(x, gl(10, 8)), sum))

On Wed, Jul 23, 2008 at 11:03 AM, Shubha Vishwanath Karanth
<shubhak at ambaresearch.com> wrote:
> Hi R,
>
>
>
> Let,
>
>
>
> x=1:80
>
>
>
> I want to sum up first 8 elements of x, then again next 8 elements of x,
> then again another 8 elements..... So, my new vector should look like:
>
> c(36,100,164,228,292,356,420,484,548,612)
>
>
>
> I used:
>
>
>
> aggregate(x,list(rep(1:10,each=8)),sum)[-1]
>
> or
>
> rowsum(x,group=rep(1:10,each=8))
>
>
>
>
>
> But without grouping, can I achieve the required? Any other ways of
> doing this?
>
>
>
> Thanks, Shubha
>
>
>
> This e-mail may contain confidential and/or privileged i...{{dropped:13}}
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paran?-Brasil
25? 25' 40" S 49? 16' 22" O