[R] Error message: missing value where logical needed

[Ben Bolker]

  I think you need something more like

MXPLOCO[is.na(MXPLOCO[i]) | MXPLOCI[i] == -9] <- NA

which will be faster (since it's vectorized rather than using a for loop) 
as well as not giving you an error.  The basic problem is that x==NA gives 
NA instead of TRUE or FALSE (since *any* operation with an NA gets 
"tainted" by the missingness of that datum).  is.na() is the way to go.
You could also look at the na.strings argument of read.table().

  Ben Bolker


On Wed, 27 Nov 2002, Haynes, Maurice (NIH/NICHD) wrote:

> Dear all,
> 
> I often import data sets from other programs that contain user defined
> missing values.  As an example consider a variable MXPLOCO with a user
> defined missing value of as -9.
> 
> > summary(MXPLOCO)
>    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's 
>  -9.000   4.750   5.000   5.349   6.000   8.500   2.000
> 
> The following command successfully converts the value -9 to NA.  However, an
> error message is also returned:
> 
> > for(i in 1:length(MXPLOCO)) {
> +     if(MXPLOCO[i] == c(-9, NA)) MXPLOCO[i] <- NA
> +     }
> Error in if (MXPLOCO[i] == c(-9, NA)) MXPLOCO[i] <- NA : 
>         missing value where logical needed
> > summary(MXPLOCO)
>    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.    NA's 
>    4.00    5.00    5.00    5.54    6.00    8.50    3.00 
> 
> What is the meaning of the error message, and how can I resolve the error?
> 
> Thanks,
> 
> Maurice
> 
> O. Maurice Haynes, Applied Statistician
> National Institute of Child Health and Human Development
> Child and Family Research Section
> 6705 Rockledge Drive
> Bethesda, MD  20892
> Voice: 301-496-8180
> Fax: 301-496-2766
> E-Mail: mh192j at nih.gov
> 
> 
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
> 

-- 
318 Carr Hall                                bolker at zoo.ufl.edu
Zoology Department, University of Florida    http://www.zoo.ufl.edu/bolker
Box 118525                                   (ph)  352-392-5697
Gainesville, FL 32611-8525                   (fax) 352-392-3704

-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._