Handling NA values

Hi,
Try this:
ifelse(rowSums(is.na(Mat))==ncol(Mat),NA,rowSums(Mat,na.rm=TRUE))
#[1]? 0? 3 NA
A.K.



----- Original Message -----
From: Christofer Bogaso <bogaso.christofer at gmail.com>
To: Marc Schwartz <marc_schwartz at me.com>
Cc: r-help <r-help at r-project.org>
Sent: Saturday, February 16, 2013 1:22 PM
Subject: Re: [R] Handling NA values

Thanks Marc for your reply.

However this leads to my problem of handling rowSums() function (hence
colSums()). Let take following matrix:

Mat <- matrix(c(1, 1, NA, -1, 1, NA, NA, 1, NA), nc = 3)
Mat

? ?  [,1] [,2] [,3]
[1,]? ? 1?  -1?  NA
[2,]? ? 1? ? 1? ? 1
[3,]?  NA?  NA?  NA

rowSums(Mat, na.rm = TRUE)

[1] 0 3 0

I want to have some way to distinguish the 1st '0' and the 3rd '0'. I
want to see NA directly for the 3rd. Any possibility how to do that
through the rowSum() function?

Thanks and regards,

On Feb 16, 2013, at 11:55 AM, Christofer Bogaso <bogaso.christofer at gmail.com> wrote:

Hello again,

I have a question on who sum() handle the NA values.

sum(c(NA, 1), na.rm = TRUE)

[1] 1


I understand this. However could not agree with following:

sum(c(NA, NA), na.rm = TRUE)

[1] 0


Where this '0' is coming from? Should not it be NA itself?

Thanks and regards,

The result of:

?  sum(c(NA, NA), na.rm = TRUE)

is to sum an empty set, hence the 0.

na.omit(c(NA, NA))

logical(0)
attr(,"na.action")
[1] 1 2
attr(,"class")
[1] "omit"

sum(logical(0))

[1] 0


If you retained the NA's, then the result is undefined:

sum(c(NA, NA))

[1] NA


See:

?  http://rwiki.sciviews.org/doku.php?id=tips:surprises:emptysetfuncs

for more information.

Regards,

Marc Schwartz

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.