[R] how to compare 2 numeric vectors

[Moshe Olshansky]

Below is one way to do this:

>
v1<-c(2,2,4,NA,NA,NA,10,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA)
>
v2<-c(NA,4,NA,NA,NA,NA,10,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,100,NA)
> length(v1)
[1] 20
> length(v2)
[1] 20
> intersect(which(!is.na(v1)),which(!is.na(v2)))
[1] 2 7
> 

--- dxc13 <dxc13 at health.state.ny.us> wrote:

> 
> useR's
> 
> I am trying to compare two vectors that have the
> same length.  More
> specifically, I am interested in comparing the
> corresponding positions of
> each element in the vector. 
> 
> Consider these two vectors of length 20:
> 
> v1 <-  2    2    4    NA  NA  NA  10  NA  NA  NA  NA
>  NA  NA  NA  NA  NA  NA 
> NA  NA  NA
> v2 <-  NA  4  NA    NA  NA  NA  10  NA  NA  NA  NA 
> NA  NA  NA  NA  NA  NA 
> NA  100 NA
> 
> I am only interested in extracting the position
> number where both vectors
> are not equal to NA at the same position.
> For example, the second element of both vectors is
> not equal to NA, and thus
> I want to return '2'; similary, I also would want to
> have '7' returned
> because the seventh element of both arrays is not
> equal to NA.
> 
> In general, I would like to find a way to do this
> for any number of given
> positions between the two vectors that satisfy this.
>  If no positions
> satisfy this, then return '0'
> 
> I would like to store the results as an object.
> 
> If anyone has any ideas, I would greatly appreciate
> it. Thanks!
> 
> dxc13
> -- 
> View this message in context:
>
http://www.nabble.com/how-to-compare-2-numeric-vectors-tf4469582.html#a12743842
> 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.
>