read and compare next observation in sas

[Aexor]

Hi,

I have this table:

id

1

0

0

0

1

0

1

I want to set a flag if any value change is there from the previous one.

as shown below:

id flag

1   N

0   Y

0  N

0  N

1  Y

0  Y

1  Y

here i tried using lag function and compare the value to get flag. Please suggest any other ways to do it.

Thanks

[Kurt_Bremser]

The LAG function is the proper tool for this, use it (Maxim 14).

[Aexor]

Thanks. yes I tried with lag function only. just wanted to check is there any other way to compare values in variable?
Can we run a loop , array ? please suggest

[PeterClemmensen]

data have;
input id;
datalines;
1
0
0
0
1
0
1
;

data want;
   set have;
   flag = ifc(id = lag(id) | _N_ = 1, "N", "Y");
run;

[singhsahab]

@Aexor alternate solution with the help of proc sql;

data have;
input id;
datalines;
5
0
0
0
1
0
1
;

proc sql noprint;
create table have1 as
select *,monotonic() as c from have;
create table WANT as
select a.id,ifc(a.id eq b.id | a.c=1,'N','Y') as flag from have1 as a left join have1 as b on a.c=b.c+1;
quit;

Thank you