Retain vs lag function

[LineMoon]

Hello experts,

Please, I would like to have the results of lag by retain function only[ i.e: w_1=lag(w), ...]

I want to use only "retain"

w	w_1	w_2	w_3
1
2	1
3	2	1
4	3	2	1
5	4	3	2
6	5	4	3
7	6	5	4
8	7	6	5
9	8	7	6
10	9	8	7
11	10	9	8
12	11	10	9
13	12	11	10
14	13	12	11
15	14	13	12
16	15	14	13

[Reeza]

I don't think that's how RETAIN works. 

What have you tried and why do you think RETAIN should be the solution?

[mkeintz]

1. Read in an observation.
   
   
2. Make an explicit output of an observation
   
   
3. followed by updating of the retained variables.
   
   

Now use this technique to experiement just with W and W_1.

[Astounding]

If your data is contained in a SAS data set, you can take advantage of the fact that all such variables are automatically retained.  Assuming that you are working with numeric variables, you could use:

data want;

w_1=w;

set have;

run;

If you want to lag for a few observations, you have to explicitly retain those variables that are not coming from a SAS data set.  For example:

data want;

w_3 = w_2;

w_2 = w_1;

w_1 = w;

set have;

retain w_1 w_2;

run;

The trick is to copy values before the SET statement replaces W.

[LineMoon]

@all: Thank you very much