[R] why order doesn't work?

[arun]

HI,

I guess you want to get the cumsum of y according to the order of x,
test1<-test[order(test$x),]
 test2<-within(test1,{cumsumy<-cumsum(y)})
 test2
#  x y cumsumy
#3 2 4       4
#1 3 8      12
#2 5 1      13
#4 6 9      22
A#5 7 0      22
A.K.





----- Original Message -----
From: cowboy <dgecon at gmail.com>
To: r-help at r-project.org
Cc: 
Sent: Friday, July 27, 2012 4:22 PM
Subject: [R] why order doesn't work?

hi all,
I want to get a cumsum according to the order of some variable.
However, it doesnt' work.
For example,
**********************
test<-data.frame(cbind(x=c(3,5,2,6,7),y=c(8,1,4,9,0)))
test[order(test$x),]$sumy<-cumsum(test[order(test$x),]$y)
**********************
R complians Warning message:
In `[<-.data.frame`(`*tmp*`, order(test$x), , value = list(x = c(2,  :
  provided 3 variables to replace 2 variables.

while the following
***********************
test$sumy<-cumsum(test[order(test$x),]$y)
******************
gives
  x y sumy
1 3 8    4
2 5 1   12
3 2 4   13
4 6 9   22
5 7 0   22

should it gives

  x y sumy
1 3 8    12
2 5 1   13
3 2 4   4
4 6 9   22
5 7 0   22

What am I missing here?
thanks,
Guang

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