Binding columns with similar column names in the same dataframe in R

Question

I have a data frame that looks somewhat like this:

df <- data.frame(0:2, 1:3, 2:4, 5:7, 6:8, 2:4, 0:2, 1:3, 2:4)
colnames(df) <- rep(c(\'a\', \'b\', \         


        

Answer 1

My version:

library(reshape)
as.data.frame(with(melt(df), split(value, variable)))
  a b c
1 0 1 2
2 1 2 3
3 2 3 4
4 0 1 2
5 1 2 3
6 2 3 4
7 0 1 2
8 1 2 3
9 2 3 4

In the step using melt I transform the dataset:

> melt(df)
Using  as id variables
   variable value
1         a     0
2         a     1
3         a     2
4         b     1
5         b     2
6         b     3
7         c     2
8         c     3
9         c     4
10        a     0
11        a     1
12        a     2
13        b     1
14        b     2
15        b     3
16        c     2
17        c     3
18        c     4
19        a     0
20        a     1
21        a     2
22        b     1
23        b     2
24        b     3
25        c     2
26        c     3
27        c     4

Then I split up the value column for each unique level of variable using split:

$a
[1] 0 1 2 0 1 2 0 1 2

$b
[1] 1 2 3 1 2 3 1 2 3

$c
[1] 2 3 4 2 3 4 2 3 4

then this only needs an as.data.frame to become the data structure you need.