retain or lag function holding a value until condition is reached

[MirLuie]

hey there!

after 5hours of trying i hope u can help me 😕

In data step i like to keep a value x of a column X that has a y value until i reach the "last" value with same y value of column Y. I tried with lag() and retain() but i did not succeed.

in a logic way it should be like: keep the x1 where Y is y1 and x1 is before y2 until the y1 that is before y2 and write x1 for x5 in X

data set is like this:

Y X
y1 x1
y2 x2
y1 x3
y1 x4
y1 x5
y2 x6


i hope soneone please coukd help me?

thank you!

[Reeza]

Show what you want as output please, it's not clear from your post.

[MirLuie]

i dont know what u mean by show it in output?

let's say it very simple: i want to use a value later in a data set.. 

[Reeza]

What do you want the output data set to look like? 

---

@MirLuie wrote:

i dont know what u mean by show it in output?

let's say it very simple: i want to use a value later in a data set.. 

---

[ErikLund_Jensen]

Hi

As I understand your problem, it is because the input data is not sorted on y and x.

The supplied code gives 2 output records: Y1 X1 and Y2 X2

data have;
	input Y$ X$;
datalines;
y1 x1
y2 x2
y1 x3
y1 x4
y1 x5
y2 x6
;
run;

proc sort data=have; by Y X;
run;

data want; set have; by Y;
	retain wantx;
	if first.y then wantx = x;
	if last.y then output;
run;

[MirLuie]

hey erik!

thanks for your suggestion.. (un)fortunately i solved my problem with lag() and delete () but I will try ur solution later... thank you very much!

[mkeintz]

I would like to see your lag/delete solution to this problem.  Please post it and mark your topic solved.