How to counting based on number of time source origination

[hoangtuyen90]

I have 2 column, column_A is origination, column B is source of origination, how to we have result in Column C

Examples: A7 - A5 is 1, A9 -- A7 is 2 due to A9 from A7 and A7 from A5, the same A10 -- A7 is 3 due to A10 from A9 and A9 from A7 and A7 from A5.

Column_A      Column_B    Result_Column_C

    A5

    A7                 A5               1

    A8                 B1               1

    A9                 A7               2

    A10               A9               3

[Kurt_Bremser]

Why does A8/B1 have a count of 1, when there is no "parent" record for B1?

[Kurt_Bremser]

If I insert an artificial "parent" obs for B1, this code works:

data have;
infile datalines truncover;
input col_a $ col_b $;
datalines;
A5
A7 A5
A8 B1
A9 A7
A10 A9
B1
;

data want;
set have;
if _n_ = 1
then do;
  declare hash a (dataset:'have (keep=col_a)');
  a.definekey('col_a');
  a.definedone();
  declare hash b (dataset:'have');
  b.definekey('col_b');
  b.definedata('col_a');
  b.definedone();
end;
if a.find(key:col_b) ne 0; /* master parent */
col_c = .;
output;
col_c = 1;
col_b = col_a;
rc = b.find();
do while (rc = 0);
  output;
  col_c + 1;
  col_b = col_a;
  rc = b.find();
end;
drop rc;
run;

[Ksharp]

It’s just one to one match ?