$VAR1 = { '' => 2, '0' => 2, 'nope' => 1, 'students' => 2, 'teacher' => 2 }; ******************************************************* greparr has 4 elements. maparr has 5 elements. grep2 has 2 elements. ******************************************************* $VAR1 = [ '', '0', 'students', 'teacher' ]; ******************************************************* $VAR1 = [ '', '0', '', 'students', 'teacher' ]; ******************************************************* $VAR1 = [ 'students', 'teacher' ]; *******************************************************