Dear Petra,
I think the easiest way, because the most flexible to me, would be to
have an object containing the indexes of the variables you want to use.
indx <- c(2,3,4,6,35) # The first column is "id" right?
dat$sums <- rowSums(dat[indx], na.rm=TRUE)
See what I mean?
There are probably other solutions, but this is what I would do.
HTH,
Ivan
Le 10/01/12 19:47, PetraOpic a écrit :
Dear Ivan,
Thank you very much for your help.
How do I use rowSums if I need to "skip" a variable from summing? (example:
sum var1, var2, var3, var5, var34 only).
Thanks in advance,
Petra Opic
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-------- Message original --------
Sujet: Fwd: [R] Sum of a couple of variables of which a few have NA values
Date : Tue, 10 Jan 2012 17:44:44 +0100
De : Ivan Calandra <ivan.calan...@u-bourgogne.fr>
Répondre à : ivan.calan...@u-bourgogne.fr
Pour : R list <r-help@r-project.org>
Hi Petra,
Try this:
dat$sums<- rowSums(dat[3:5], na.rm=TRUE)
I think this should do what you're looking for
HTH,
Ivan
-------- Message original --------
Sujet: [R] Sum of a couple of variables of which a few have NA values
Date : Tue, 10 Jan 2012 17:25:21 +0100
De : Petra Opic<petrao...@gmail.com>
Pour : r-help@r-project.org
Dear everyone,
I have looked all over the internet but I cannot find a way to solve my problem.
In my data I want to sum a couple of variables. Some of these
variables have NA values, and when I add them together, the result is
NA
dat<- data.frame(
id = gl(5,1),
var1 = rnorm(5, 10),
var2 = rnorm(5, 7),
var3 = rnorm(5, 6),
var4 = rnorm(5, 3),
var5 = rnorm(5, 8)
)
dat[3,3]<- NA
dat[4,5]<- NA
dat
id var1 var2 var3 var4 var5
1 1 9.371328 7.830814 5.032541 3.491053 7.626418
2 2 10.413516 7.333630 6.557178 1.465597 8.591770
3 3 10.967073 NA 6.674079 3.946451 7.251263
4 4 9.900380 7.727111 5.059698 NA 6.632962
5 5 9.191068 7.901271 6.652410 2.734856 8.484757
attach(dat)
dat$sum<- var2 + var3 + var4 # I think I'm doing this wrong, but I
don't know what command to use
dat
id var1 var2 var3 var4 var5 sum
1 1 9.371328 7.830814 5.032541 3.491053 7.626418 16.35441
2 2 10.413516 7.333630 6.557178 1.465597 8.591770 15.35640
3 3 10.967073 NA 6.674079 3.946451 7.251263 NA
4 4 9.900380 7.727111 5.059698 NA 6.632962 NA
5 5 9.191068 7.901271 6.652410 2.734856 8.484757 17.28854
I would like to omit the values of NA and just sum the rest.
I tried to use rowSums() but that sums an entire row and I only need a
few variables.
Does anyone know how to do this?
Thanks in advance,
Petra
______________________________________________
R-help@r-project.org mailing list
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and provide commented, minimal, self-contained, reproducible code.
--
Ivan CALANDRA
Université de Bourgogne
UMR CNRS 5561 Biogéosciences
6 Boulevard Gabriel
21000 Dijon, FRANCE
ivan.calan...@u-bourgogne.fr
______________________________________________
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