Search and combine text from the same columns related to a specific variable in R

Question

i have the following example data frame in R:

ID = c(rep(1,4),rep(2,3),rep(3,2),4,5);ID
VAR = c(rep("A",3),"B",rep("C",2),"D",rep("E",2),"F","G");VAR
D = data.frame(ID,VAR);D

My purpose is to construct a separate variable outside the data frame that will search all the ids and print the combined texts related to each id. For example the data frame

ID	VAR
1	A
1	A
1	A
1	B
2	C
2	C
2	D
3	E
2	E
4	F
5	G

ideal output given the above data frame in R will be :

ID	TEXTS
1	A,B
2	C,D
3	E
4	F
5	G

Any help ?

Answer 1

You can try this

> aggregate(. ~ ID, unique(D), c)
  ID  VAR
1  1 A, B
2  2 C, D
3  3    E
4  4    F
5  5    G

or

> aggregate(. ~ ID, unique(D), toString)
  ID  VAR
1  1 A, B
2  2 C, D
3  3    E
4  4    F
5  5    G