my @student_list;
push @student_list, { studentName => 'John', studentSurname=>'Something',  studentID=>'9534', age=>'12' };
push @student_list, { studentName => 'Mary' ,studentSurname=>'Something2',  studentID=>'5489', age=>'13' };

##</code><code>##

0  HASH(0x80355e98)
   'classroomID' => 10
   'classroomName' => 'classroom1'
   'students' => ARRAY(0x80359e18)
      0  HASH(0x8006c050)
         'age' => 12
         'studentID' => 9534
         'studentName' => 'John'
         'studentSurname' => 'Something'
      1  HASH(0x8032f958)
         'age' => 13
         'studentID' => 5489
         'studentName' => 'Mary'
         'studentSurname' => 'Something2'

##</code><code>##

 print $classrooms[0]{students}[1]{'studentSurname'}; # prints 'Something2'

##</code><code>##

print $classrooms[0]->{students}->[1]->{'studentSurname'}; # prints 'Something2'