Retain

[Ronein]

Hello

I would like to retain the value of column Z for each customer.

The input data set has  2 columns: ID ,Z

1 10
1 15
1 20
2 50
2 45
2 55
3 40
3 42
3 38

The desired data set will have the following columns ID,Z,First_Z with following values:

1 10 10
1 15 10
1 20 10
2 50 50
2 45 50
2 55 50
3 40 40
3 42 40
3 38 40

What is the way to do it using Retain statement?

Data tbl;
input ID Z;
cards;
1 10
1 15
1 20
2 50
2 45
2 55
3 40
3 42
3 38
;
run;

[Jagadishkatam]

proc sort data=tbl;
by id;
run;

data want;
set tbl;
by id;
retain newvar;
if first.id then newvar=z;
run;

[PeterClemmensen]

Data tbl;
input ID Z;
cards;
1 10
1 15
1 20
2 50
2 45
2 55
3 40
3 42
3 38
;
run;

data want;
   set tbl;
   by ID;
   if first.ID then First_Z=Z;
   retain First_Z;
run;