[R] Replace NAs in one column with data from another column

[Bert Gunter]

with() would seem to be useful here:

m$z <- with(m,ifelse(is.na(z), x, z))

(I believe the timing is similar, but haven't checked)

-- Bert

On Wed, Sep 8, 2010 at 11:22 AM, Dimitris Rizopoulos
<d.rizopoulos at erasmusmc.nl> wrote:
> one way is the following:
>
> m <- data.frame(x = rnorm(100), y = rnorm(100), z = rnorm(100))
> m$z[sample(100, 20)] <- NA
>
> m$z.new <- ifelse(is.na(m$z), m$x, m$z)
>
>
> I hope it helps.
>
> Best,
> Dimitris
>
>
> On 9/8/2010 8:17 PM, Jakob Hedegaard wrote:
>>
>> Hi list,
>>
>> I have a data frame (m) with 169221 rows and 10 columns and would like to
>> make a new column containing the content of column 3 but replace the NAs in
>> column 3 with the data in column 1 (from the same row as the NA in column
>> 3). Column 1 has data in all rows.
>>
>> My first attempt was:
>>
>> for (i in 1:169221){
>> if (is.na(m[i,3])==TRUE){
>> m[i,11]<- as.character(m[i,1])}
>> else{
>> m[i,11]<- as.character(m[i,3])}
>> }
>>
>> Works - but takes too long time.
>> I would appreciate alternative solutions.
>>
>> Best regards, Jakob
>>
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>>
>
> --
> Dimitris Rizopoulos
> Assistant Professor
> Department of Biostatistics
> Erasmus University Medical Center
>
> Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
> Tel: +31/(0)10/7043478
> Fax: +31/(0)10/7043014
>
> ______________________________________________
> 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.
>