[R] Looping Over Data Frames

[David Winsemius]

On Apr 29, 2013, at 6:03 PM, Sparks, John James wrote:

> Dear R Helpers,
> 
> I am re-phrasing a question that I put forth earlier today due to some
> particulars in the solution that I am searching for.  Many thanks to those
> who answered the previous post and to any who would be willing to answer
> this one.
> 
> I have a set of data frames.  I need to perform some data scrubbing on
> each of them.  I am trying to figure out how to perform the same steps on
> each data frame using some sort of loop or something along those lines.
> 
> Because my actual data frames are quite large and the steps I am taking
> moderately complicated, I would very much prefer not to put them all
> together in a list because when I get an error, I can't determine which
> part of the list is the source of the error.  So, I would really
> appreciate it if someone could post a way to perform the following sub
> setting function on the three simple data frames in the example below with
> some sort of loop or something along those lines, which would work
> directly on the data frames in question.
> 
> Many thanks in advance.  Please let me know if there is anything I can do
> to make the question more clear.
> 
> --John Sparks
> 
> 
> x=as.data.frame(matrix(c(1,2,3,
>        1,2,3,
>        1,2,2,
>        1,2,2,
>       1,1,1),ncol=3,byrow=T))
> 
> y=as.data.frame(matrix(c(1,2,3,
>        1,2,3,
>        1,2,2,
>        1,2,2,
>       1,1,1),ncol=3,byrow=T))
> 
> z=as.data.frame(matrix(c(1,2,3,
>        1,2,3,
>        1,2,2,
>        1,2,2,
>       1,1,1),ncol=3,byrow=T))
> 
> #Want to build some sort of loop for this.
> x<-subset(x,select=-c(V1))
> y<-subset(y,select=-c(V1))
> z<-subset(z,select=-c(V1))


> for(i in letters[24:26] ) assign( i, subset(get(i), select=-c(V1))  )
> x
  V2 V3
1  2  3
2  2  3
3  2  2
4  2  2
5  1  1


-- 

David Winsemius
Alameda, CA, USA