Nice shot of cumsum(). Just improve it a little:
> x <- c(0,0,1,2,3,0,0,4,5,6)
> x.groups <- split(x, (x != 0) * cumsum(x == 0))[-1]
> x.groups
$`2`
[1] 1 2 3
$`4`
[1] 4 5 6
> lapply(x.groups, mean)
$`2`
[1] 2
$`4`
[1] 5
On Mon, Mar 8, 2010 at 11:02 AM, jim holtman wrote:
> Try this:
>
>> x <
e explain that?
>
> Thanks,
>
> -Original Message-
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org]
> On
> Behalf Of jim holtman
> Sent: 08 March 2010 08:32
> To: Daren Tan
> Cc: r-h...@stat.math.ethz.ch
> Subject: Re: [R] Average r
Behalf Of jim holtman
Sent: 08 March 2010 08:32
To: Daren Tan
Cc: r-h...@stat.math.ethz.ch
Subject: Re: [R] Average regions of non-zeros
Try this:
> x <- c(0,0,1,2,3,0,0,4,5,6)
> # partition the data
> x.p <- split(x, cumsum(x == 0))
> # now only process groups > 1
> x.mean
try this:
x <- c(0,0,1,2,3,0,0,4,5,6)
rl <- rle(x == 0)
grp <- rep(seq_along(rl$lengths), rl$lengths)
res <- tapply(x, grp, mean)
res[res > 0]
I hope it helps.
Best,
Dimitris
On 3/8/2010 3:48 AM, Daren Tan wrote:
x<- c(0,0,1,2,3,0,0,4,5,6)
How to identify the regions of non-zeros and a
Try this:
> x <- c(0,0,1,2,3,0,0,4,5,6)
> # partition the data
> x.p <- split(x, cumsum(x == 0))
> # now only process groups > 1
> x.mean <- lapply(x.p, function(a){
+ if (length(a) == 1) return(NULL)
+ return(list(grp=tail(a, -1), mean=mean(tail(a, -1
+ })
> # now only return the real
x <- c(0,0,1,2,3,0,0,4,5,6)
How to identify the regions of non-zeros and average c(1,2,3) and c(4,5,6) to
get 2 and 5.
Thanks
_
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