[R] Subtotals by id for a large number of columns XXXX

[David Winsemius]

On Oct 30, 2013, at 4:07 AM, Dan Abner wrote:

> Hi everybody,
> 
> I have data in the format of the example data below where essentially a
> large number of indicator variables (coded [0,1]) reflect traits of the
> same id across multiple rows. I need to represent the data in a 1 row per
> id format. I see this as being similar to converting from long to wide
> format, however, there is no time component here: The multiple rows here
> are all characteristics observed at the same measurement occasion. So,
> really I just need an individual sum for each variable (for a large number
> of variables) and for these to be all saved in the same row (along with the
> id variable and other demographics (e.g., "location").
> 
> Here is the example df and the method I used first:
> 
> 
> d1<-data.frame(id=c(1,1,1,2,2,2,2,3,3,4),location=factor(c(rep(0,7),rep(1,3)),
> labels=c("A","B")),var1=as.logical(round(runif(10))),
> var2=as.logical(round(runif(10))),var3=as.logical(round(runif(10))))
> d1

Perhaps.

> mysum<-aggregate(d1[-(1:2)],by=d1[1:2] ,sum)
> mysum
  id location var1 var2 var3
1  1        A    0    2    1
2  2        A    1    2    1
3  3        B    1    0    2
4  4        B    1    1    0

> 
> 	[[alternative HTML version deleted]]

Please learn to use your mail client to post in plain text. (All of the free mailer services support plain text, so continuing to post in HYML is evidence of willful refusal to adhere to the posting guidelines.)

-- 
David Winsemius
Alameda, CA, USA