>perl -wMstrict -le
"sub my_split {
   my ($elem, $rx, $string) = @_;
   return (split $rx, $string, $elem+2)[$elem];
   }
 my $s = 'a:b:c:d:e';
 print q{'}, my_split($_, ':', $s), q{'} for 0, 1, 3, 4, 5, 9999;
"
'a'
'b'
'd'
'e'
''
''