[R] matrix logic

[Tom]

On Tue, 10 Jan 2006 20:25:23 -0500, r user <ruser2006 at yahoo.com> wrote:

> I have 2 dataframes, each with 5 columns and 20 rows.
> They are called data1 and data2.I wish to create a
> third dataframe called data3, also with 5 columns and
> 20 rows.
>
> I want data3 to contains the values in data1 when the
> value in data1 is not NA.  Otherwise it should contain
> the values in data2.
>
> I have tried afew methids, but they do not seem to
> work as intended.:
>
> data3<-ifelse(is.na(data1)=F,data1,data2)
>
> and
>
> data3[,]<-ifelse(is.na(data1[,])=F,data1[,],data2[,])
>
> Please suggest the â€œbestâ€ way.
>
Not sure about the bast but...

a<-c(1,2,3,NA,5)
b<-c(4,4,4,4,4)

c<-a
c[which(is.na(a))]<-b[which(is.na(a))]




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