options source2 ;

%inc 'Lexis.sas' ;
%inc 'PYtab.sas' ;

* A (very) small cohort study ;
data a ;
  input id entry exit fail ;
  informat entry exit ddmmyy8. ;
    format entry exit ddmmyy10. ;
  cards ;
1 14/07/52 13/03/91 1
2 03/04/41 17/07/68 2
3 23/03/56 21/05/96 0
4 24/07/49 23/06/99 1
5        . 24/12/97 0
6        .        . 1
7 11/03/55 13/04/87 .
8 14/07/52 01/01/56 0
9 14/07/52 01/01/56 1
;
run ;

proc print   data = a ;
    run ;

* Split follow-up in intervals after entry ;
    
%Lexis ( data = a,
          out = b,
       origin = entry, 
        scale = 365.25,
       breaks = %str( 0.5,1,3,4,5,7,10,12,13,35,50 ),
         left = tfe,
        right = right,
         lint = length,
      os_left = olf,
     os_right = ort,
      os_lint = olg,
         cint = icens,
         nint = intno,
        other = %str( format olf ort ddmmyy10. ;
                        label tfe = "Time since entry" ; )
           ) ;

proc contents data = b ; run ;
proc print data = b ; run ;
proc print data = discrd ; run ;

%PYtab( data=b, class=tfe ) ;

* Split the time along calendar time axis, note the scale for
  risk time: it is days as enter and exit are date variables ;
%Lexis ( data = a,
         breaks = %str('7jan49'd to '9dec95'd by 3*365+366, '9dec97'd)
          ) ;

proc print data = a ;
run ;