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Sequence Array

Occasional Contributor
Posts: 14

Sequence Array

I am working with a transaction type data set where there are multiple observations for individual children.  Each child has a unique "child_id" and there are multiple observations, for which the child has an associated value for the variable TREATMENT.  There may or may not be repeats for the values of TREATMENT.

There are around 80,000 children. There an indefinite number of TREATMENT paths based on around 30 TREATMENT types.

The following is similar to what the data currently looks like:

Child          Treatment

1                    A

1                    C

1                    C

1                    D    

1                    B

2                    B

2                    B

2                    A

2                    B

The following is just a brief example of what I would like the data to look like. The TREATMENT should only increment when the treatment type has changed.

Child    Treatment_1      Treatment_2     Treatment_3     Treatment_4     Treatment_n

   1            A                         C                     D                    B                      

   2            B                         A                     B                                       


Thank you for your insight

Posts: 7,363

Re: Sequence Array

data need;

  set have;

  by child treatment notsorted;

  if last.treatment then output;


proc transpose data=need out=want prefix=treatment_;

  by child;

  var treatment;


Super Contributor
Posts: 254

Re: Sequence Array

Another Solution with Data Step.

You need to have the data set, HAVE. to be pre-sorted by Child.

The array size is taken as 4 but can be extended as desired.

data want;

array t

  • $1 Treatment_1 - Treatment_4;
  • do until(last.Child);

       set have;

       by Child;

       if first.Child then i = 1; t = Treatment; i + 1; end;

       else if Treatment ^= t[i - 1] then do; t = Treatment; i + 1; end;


    drop i Treatment;


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