Conditional retain

[vidyasagar1]

data one;
 infile datalines;
 input Level 1. Component $5.;
 datalines;
1	78950
2	78951
3	67890
4	31234
4	45678
4	45679
4	34567
3	89456
4	89012
4	89015
4	67892
3	89016
2	76548
3	89456
4	89765
1	78951
2	99987
3	89891
4	77889
4	77989
4	79867
4	98765
3	89763
4	98657
4	67543
4	45637
;run;

I have data like above and i need to get the output like below;

Level	Component	Component_New
1	78950	78950
2	78951	78950
3	67890	78951
4	31234	67890
4	45678	67890
4	45679	67890
4	34567	67890
3	89456	67890
4	89012	67890
4	89015	67890
4	67892	67890
3	89016	78951
2	76548	78950
3	89456	76548
4	89765	89456
1	78951	78951
2	99987	78951
3	89891	99987
4	77889	89891
4	77989	89891
4	79867	89891
4	98765	89891
3	89763	99987
4	98657	89763
4	67543	89763
4	45637	89763

[ballardw]

So what is rule (or rules) involved in which value is "retained"?

I do not see any obvious pattern so you need to supply details.

[vidyasagar1]

If level=1 then component_new=component and if level=2 then component_new=component of Level1 and if level=3 then component_new=component of Level2 and if level=4 then component_new=component of Level3 and so on.

If level=1 component value changes then component_new for Level2 has to retain new value.

If level=2 component value changes then component_new for Level3 has to retain new value and so on.

[Patrick · Accepted solution]

@vidyasagar1 

Below code returns how I understand the logic you describe. The result differs slightly from what you've posted as desired result.

I assumed typos in your desired result. If that's not the case then can you please explain the logic required to get to the values where the numbers differ.

data one;
  infile datalines;
  input Level 1. Component $6.;
  datalines;
1 78950
2 78951
3 67890
4 31234
4 45678
4 45679
4 34567
3 89456
4 89012
4 89015
4 67892
3 89016
2 76548
3 89456
4 89765
1 78951
2 99987
3 89891
4 77889
4 77989
4 79867
4 98765
3 89763
4 98657
4 67543
4 45637
;
run;

data want;
  set one;
  by level notsorted;
  array _comp_new {0:9} $6 _temporary_;
  if last.level then
    do;
      _comp_new[level]=Component;
      if level=1 then _comp_new[0]=Component;
    end;
  Component_New=_comp_new[level-1];
run;

[vidyasagar1]

Thank you so much i struggled a lot for this.

I greatly appreciate your help.