C:\Perl\bin>perl N:\Perle\Learn\DateTime\pm_1033231_orig_analyse_003_h.pl This is the set with defined 'end': 2013-05-14T00:00:00 2013-05-28T00:00:00 2013-06-11T00:00:00 2013-06-25T00:00:00 2013-07-09T00:00:00 2013-07-23T00:00:00 2013-08-06T00:00:00 TESTING whether Date is in set... 1 2013-05-14 0 2013-05-21 1 2013-05-28 0 2013-06-04 1 2013-06-11 0 2013-06-18 This is the begin of the set with 'end' commented out: 2013-05-14T00:00:00 2013-05-28T00:00:00 2013-06-11T00:00:00 2013-06-25T00:00:00 2013-07-09T00:00:00 2013-07-23T00:00:00 2013-08-06T00:00:00 TESTING whether Date is in set... 1 2013-05-14 1 2013-05-21 1 2013-05-28 1 2013-06-04 1 2013-06-11 1 2013-06-18