On Fri, Mar 20, 2009 at 7:18 PM, science! <karthik.ram at gmail.com>
wrote:>
> I am aware that it is easily possible to create var names on the fly. e.g.
> assign(paste("m",i,sep=""),j)
> but is it possible to assign dataframes to variables created on the fly?
>
> e.g.
> If I have a dataframe called master and I wanted to subset parts of those
> data into separate dataframes, I could do:
>
> m1=subset(master,master$SAMPLE=='1')
> m2=subset(master,master$SAMPLE=='2')
> .....
>
> but I would like to do this in a loop. Can someone give me suggestions on
> how to accomplish this?
>
>
> I tried
assign(paste("m",i,sep=""),subset(master,master$SAMPLE==i)
with no
> success.
>
Are you sure you really need to name these dataframes?
Here's a workaround that I use for these cases. Create your new data
frames and add them to a list, as in
myframes <- list(subset(master,master$SAMPLE=='1'),
m2=subset(master,master$SAMPLE=='2'))
Then when you want to use these things, you can get the first one as
myframes[[1]]
or myframes[[2]].
You can name the objects inside the list:
names(myframes) <- c("A","B")
This is just as good as referring to them by name, in my experience.
It also has the benefit that because your dataframes are in a list,
then you can use features like lapply to do things for each dataset.
I'm reading ?assign now, and it appears you can actually name these things.
> name <- paste("fred",4,sep="")
> x <- data.frame(py=rnorm(10))
> assign(name,x)
> ls()
[1] "fred4" "mname" "name"
"x"> name
[1] "fred4"> fred4
py
1 -1.04243477
2 -0.66475049
3 -0.08576428
4 0.64369356
5 -0.06828696
6 1.15710627
7 -2.45041700
8 0.40139655
9 0.27320936
10 -0.98028020
pj
--
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas