HI,
Not sure I understand it correctly,
data1<-read.table(text="
a b c d
0 1 1 0
1 1 1 1
1 0 0 1
",sep="",header=TRUE)
data2<- data1
data3<- data1
If i follow this logic for the 1st and 2nd columns,
data1[ data1[ , 4 ] == 0 , 1 ] <- NA
data1[ data1[ , 4 ] == 0 , 2 ] <- NA
data1
# a b c d
#1 NA NA 1 0
#2 1 1 1 1
#3 1 0 0 1
Still, the column 'b' with 0 element is left as such while and `1` in b is
replaced with NA
data2[,1][data2[,4]==0 & data2[,1]==0]<- NA
data2[,2][data2[,4]==0 & data2[,2]==0]<- NA
data2
# a b c d
#1 NA 1 1 0
#2 1 1 1 1
#3 1 0 0 1
#or you can try
data3[,1:2]<- lapply(letters[1:2],function(x)
{x1<-cbind(data3[,x],data3[,4]);colnames(x1)<- c(x,"d");x1;
x1[rowSums(x1)==0,1]<-NA;x1[,1]})
data3
# a b c d
#1 NA 1 1 0
#2 1 1 1 1
#3 1 0 0 1
A.K.
----- Original Message -----
From: Anthony Damico <ajdam...@gmail.com>
To: Camilo Mora <cm...@dal.ca>
Cc: R help <r-help@r-project.org>
Sent: Saturday, March 2, 2013 6:10 AM
Subject: Re: [R] replace zeros for NA in a column based on values of another
column
you want to replace all rows where the 4th column is zero.. (data[ , 4 ]
== 0)
and you want to perform that replacement in the first column..
so try
data[ data[ , 4 ] == 0 , 1 ] <- NA
On Sat, Mar 2, 2013 at 5:26 AM, Camilo Mora <cm...@dal.ca> wrote:
> Hi everyone,
>
> Imagine that I have a data frame with four columns:
> data<-
> a b c d
> 0 1 1 0
> 1 1 1 1
> 1 0 0 1
>
> I want to replace the zeros in columns a:b for NA only for the rows in
> which column d are zero. So
>
> a b c d
> NA 1 1 0
> 1 1 1 1
> 1 0 0 1
>
> I am trying this:
> data[,1:3][data[4] == 0] <- NA
> But get this error:
>
> Error in `[<-.data.frame`(`*tmp*`, Data[4] == 0, value = NA) :
> only logical matrix subscripts are allowed in replacement
>
> Does anyone knows the reason of this error or is there an alternative to
> replace the values in one column based on the values of another?
>
> Thanks,
>
> Camilo
>
> Camilo Mora, Ph.D.
> Department of Geography, University of Hawaii
> http://www.soc.hawaii.edu/**mora/ <http://www.soc.hawaii.edu/mora/>
>
> ______________________________**________________
> R-help@r-project.org mailing list
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