On Nov 24, 2014, at 3:12 PM, Dimitri Liakhovitski wrote:
> I have the data frame 'df' and my desired solution 'out'.
> I am sure there is a more elegant R-way to do it - without a loop.
>
> df = data.frame(a=1:5,b=letters[1:5],c1=1:5,c2=2:6,c3=3:7,c4=4:8)
> mylist=NULL
> for(i in 1:4){
> myname<-paste("c",i,sep="")
> mylist[[i]]<-df[c("a","b",myname)]
> names(mylist[[i]])<-c("a","b","c")
> }
> out<-do.call(rbind,mylist)
> out
>
Observe the wonders of recycling in dataframes. If you wanted to drop the last
column from this it would be the same modulo changing one column nmae.
cbind( df[1:2], stack(df[-c(1:2)] ) )
#
a b values ind
1 1 a 1 c1
2 2 b 2 c1
3 3 c 3 c1
4 4 d 4 c1
5 5 e 5 c1
6 1 a 2 c2
7 2 b 3 c2
8 3 c 4 c2
9 4 d 5 c2
10 5 e 6 c2
11 1 a 3 c3
12 2 b 4 c3
13 3 c 5 c3
14 4 d 6 c3
15 5 e 7 c3
16 1 a 4 c4
17 2 b 5 c4
18 3 c 6 c4
19 4 d 7 c4
20 5 e 8 c4
--
David Winsemius
Alameda, CA, USA
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