[R] sum portions of a vector

[arun]

Hi,
May be this also helps:
do.call(rbind,lapply(split(vec,findInterval(vec,c(4,9))),function(x) paste0(sum(x),"=",paste(x,collapse="+"))))
  [,1]          
#0 "6=1+2+3"     
#1 "30=4+5+6+7+8"
#2 "19=9+10"     
a.K.



----- Original Message -----
From: Sam Steingold <sds at gnu.org>
To: r-help at r-project.org
Cc: 
Sent: Monday, December 10, 2012 2:29 PM
Subject: [R] sum portions of a vector

How do I sum portions of a vector into another vector?
E.g., for
--8<---------------cut here---------------start------------->8---
> vec <- 1:10
> breaks <- c(3,8,10)
--8<---------------cut here---------------end--------------->8---
I want to get a vector of length 3 with content
--8<---------------cut here---------------start------------->8---
6 = 1+2+3
30 = 4+5+6+7+8
19 = 9+10
--8<---------------cut here---------------end--------------->8---
Obviously, I could write a loop, but I would rather have a vectorized
version.
Thanks!

-- 
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
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