Data Manipulation

[Phamhhm]

Hi,

Some values of my var X are 0, and i want to replace all of them by the previous value.

X    Xnew

1     1

2     2

0     2

4     4

3     3

0     3

7     7

My code does not work:

DATA  Tnew;

SET     Told;

IF X=0 THEN Xnew=lag(X);

RUN;

thank for your help

[novinosrin]

data have;
input X ;   
cards;
1     1
2     2
0     2
4     4
3     3
0     3
7     7
;

data want;
set have;
x=ifn(x=0,lag(x),x);
run;

[novinosrin]

data have;
input X ;   
cards;
1     1
2     2
0     2
4     4
3     3
0     3
7     7
;

data want;
set have;
xnew=ifn(x=0,lag(x),x);
run;

[Phamhhm]

Thank for your answer, the code works, but i forgot something

X    Xnew

1     1

2     2

0     2

4     4

3     3

0     3

0     3

4     4

5     5

0     5

0     5

0     5

some rows have 2 or 3 consecutive zeros

[novinosrin]

Ok @Phamhhm 

Try

data have;
input X ;   
cards;
1     1
2     2
0     2
4     4
3     3
0     3
0     3
4     4
5     5
0     5
0     5
0     5
;

data want;
set have;
retain temp;
temp=ifn( x=0 and lag(x) ne 0 ,lag(x),temp);
xnew=ifn( x=0,temp,x);
drop temp;
run;

[novinosrin · Accepted solution]

Hi @Phamhhm 

Forget the lag function, Just retain will do

data have;
input X ;   
cards;
1     1
2     2
0     2
4     4
3     3
0     3
0     3
4     4
5     5
0     5
0     5
0     5
;
data want;
set have;
retain t;
if x ne 0 then do;
t=x;
xnew=x;
end;
else xnew=t;
drop t;
run;

[Phamhhm]

Thank you, problem solved