R help - Jan 2009 - prblem with NA

Hi all

I have a data set with the total number of columns =ncol, and the total
number of rows=nrow. I am trying to loop over the values and id the value is
less than or equal to 100 to be changed to 1. if the value is greater than
100 , to be changed to 0. if NA , let X[i,j]=NA. I ran into a problem where
if one row in my data set had all values =NA, then the program does not
continue working past that row!  

At some point I get the following error message:

?Error in if (data [i, j] <= 100) { : missing value where TRUE/FALSE needed?

Here is the program 

data<-read.table("fileName.txt", header=F, sep='\t')

X=data
for(i in ncol)
{
for(j in nrow)
{
if(data[i,j]<=100) {X[i,j]=1}
if(data[i,j]>100) {X[i,j]=0}

if(is.na(data[i,j])) {X[i,j]=NA}
}
}

Thanks 

-- 
View this message in context:
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Sent from the R help mailing list archive at Nabble.com.

Try vectorizing instead of a loop:
> da <- matrix(nrow=10,ncol=10)
> n <- sample(1:100, 40)
> da[n[1:20]] <- 99
> da[n[21:40]] <- 199
> X <- ifelse(is.na(da), NA, ifelse(da <= 100, 1, 0))
>
>
> X
      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
 [1,]   NA   NA   NA   NA   NA    1   NA   NA   NA    NA
 [2,]   NA   NA    1    0   NA   NA   NA   NA   NA    NA
 [3,]    1   NA    0    1    1   NA    0    0    1    NA
 [4,]   NA   NA    0   NA    1    1    1    0   NA    NA
 [5,]   NA   NA    0   NA    1    1    1    1   NA    NA
 [6,]   NA   NA    0    0   NA    0   NA   NA    0    NA
 [7,]    1   NA    1   NA   NA   NA   NA    1   NA    NA
 [8,]   NA   NA   NA   NA   NA    0    1    0   NA     1
 [9,]    1   NA   NA    1    0    0    0    0   NA    NA
[10,]   NA    0   NA   NA    0   NA    0   NA   NA    NA
>

On Mon, Jan 5, 2009 at 6:21 PM, kayj <kjaja27 at yahoo.com>
wrote:
>
>
> Hi all
>
> I have a data set with the total number of columns =ncol, and the total
> number of rows=nrow. I am trying to loop over the values and id the value
is
> less than or equal to 100 to be changed to 1. if the value is greater than
> 100 , to be changed to 0. if NA , let X[i,j]=NA. I ran into a problem where
> if one row in my data set had all values =NA, then the program does not
> continue working past that row!
>
> At some point I get the following error message:
>
> "Error in if (data [i, j] <= 100) { : missing value where
TRUE/FALSE needed"
>
> Here is the program
>
> data<-read.table("fileName.txt", header=F, sep='\t')
>
> X=data
> for(i in ncol)
> {
> for(j in nrow)
> {
> if(data[i,j]<=100) {X[i,j]=1}
> if(data[i,j]>100) {X[i,j]=0}
>
> if(is.na(data[i,j])) {X[i,j]=NA}
> }
> }
>
> Thanks
>
> --
> View this message in context:
http://www.nabble.com/prblem-with-NA-tp21301527p21301527.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> 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.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

Hello -

kayj wrote:
> 
> Hi all
> 
> I have a data set with the total number of columns =ncol, and the total
> number of rows=nrow. I am trying to loop over the values and id the value
is
> less than or equal to 100 to be changed to 1. if the value is greater than
> 100 , to be changed to 0. if NA , let X[i,j]=NA. I ran into a problem where
> if one row in my data set had all values =NA, then the program does not
> continue working past that row!  
> 
> At some point I get the following error message:
> 
> ?Error in if (data [i, j] <= 100) { : missing value where TRUE/FALSE
needed?
> 
> Here is the program 
> 
> data<-read.table("fileName.txt", header=F, sep='\t')
> 
> X=data
> for(i in ncol)
> {
> for(j in nrow)
> {
> if(data[i,j]<=100) {X[i,j]=1}
> if(data[i,j]>100) {X[i,j]=0}
> 
> if(is.na(data[i,j])) {X[i,j]=NA}
> }
> }

An alternate, vectorized solution may be:

X <- ifelse(data <= 100, 1, 0)

And as 'data' is a function in the utils package include with R, you 
might consider not naming your variables 'data'.