Replicate every id by all possible unique group present in data

[Miracle]

Dear All,
Can I please seek your help on how to achieve this?
For example, I would like turn data X into data Y.

Thanks a lot.

Data X	Data Y
id  grp	id  grp
1  A	1  A
1  B	1  B
2  A	1 C
2  C	2  A
3  A	2 B
3  B	2  C
3  C	3  A
4  C	3  B
	3  C
	4  A
	4  B
	4  C

[maguiremq · Accepted solution]

data x;
input id grp $1.;
datalines;
1 A
1 B
2 A
2 C
3 A
3 B
4 C
;

proc freq
	data = x noprint;
		tables id * grp / 	sparse 
							out = y (drop = count percent);
run;

id grp 
1 A 
1 B 
1 C 
2 A 
2 B 
2 C 
3 A 
3 B 
3 C 
4 A 
4 B 
4 C 

I prefer the SPARSE statement with PROC FREQ to do things like this.

[Miracle]

Thanks @maguiremq for your quick reply.
I was thinking something like datastep by reading a macro variable containing all the unique grp then using do loop to repeat for every row but I dunno how exactly.
This is much easier and should do for now.