If I construct a data frame as
# constructing df
a <- c(rep("A", 3), rep("B", 3), rep("A",2))
b <- c(1,1,2,4,1,1,2,2)
#c <- c("ir", "ir", "br", "ir", "us", "us", "ir", "br")
c <- c(1, 2, 3, 4, 4, 4, 4, 5)
df <- data.frame(a,b,c)
I can aggregate that via:
df_red <- aggregate(list(track = c), df[,c("a", "b")], '[')
What is the best way to disaggregate that back to what it was before?
IN another words, how can I convert this:
a b track
1 A 1 1, 2
2 B 1 4, 4
3 A 2 3, 4, 5
4 B 4 4
to this:
a b c
1 A 1 1
2 A 1 2
3 A 2 3
4 B 4 4
5 B 1 4
6 B 1 4
7 A 2 4
8 A 2 5