24793 - Validating date continuity within a BY-Group

Sample 24793: Validating date continuity within a BY-Group

/* To check for continuous coverage, create three temporary variables */
/* which hold the earliest beginning date of coverage, the last date  */
/* of coverage, and the number of days that have lapsed, if any.      */

data one;
  input id $ begin :yymmdd10. end :yymmdd10.;
datalines;
A 1996-01-01 1996-06-30
A 1996-02-01 1996-04-30
A 1996-03-01 1996-03-31
A 1996-08-01 1996-09-30
B 1996-01-01 1996-01-31
B 1996-02-01 1996-03-31
B 1996-04-01 1996-06-30
B 1996-07-02 1996-08-31
B 1996-09-05 1996-09-30
;

proc sort data=one ;
  by id begin;
run;


/* Reassign temporary variables when the BY-Group changes. For every */
/* other observation, check to see if the current observation value  */
/* of BEGIN falls within RBEGIN and REND + one. If it does, there is */
/* no break in coverage. If END is greater than REND, reassign REND. */
/* Else, if there is a break in same BY-Group, calculate lapse and   */
/* reassign temporary variables for 'new coverage' dates.            */

data two;
  set one;
  by id begin;
  retain rbegin rend breakday;
  drop rbegin rend;

  if first.id then do;
    rbegin=begin;
    rend=end;
    breakday=0;
  end;

  else do;
    if rbegin<=begin <=rend +1 then do;
      breakday=0;
      if end > rend then rend=end;
    end;

    else if begin>rend+1 then do;
      breakday=begin-rend-1;
      rbegin=begin;
      rend=end;
    end;

  end;
run;

proc print;
run;

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Obs    id    begin     end     breakday

1     A     13149    13330        0
2     A     13180    13269        0
3     A     13209    13239        0
4     A     13362    13422       31
5     B     13149    13179        0
6     B     13180    13239        0
7     B     13240    13330        0
8     B     13332    13392        1
9     B     13397    13422        4

Type:	Sample
Topic:	SAS Reference ==> DATA Step Data Management ==> Manipulation and Transformation ==> BY-group processing

Date Modified:	2005-12-08 11:34:35
Date Created:	2004-09-30 14:09:14

Product Family	Product	Host	SAS Release
			Starting	Ending
SAS System	Base SAS	All	n/a	n/a

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Sample 24793: Validating date continuity within a BY-Group

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