#!/usr/bin/perl 

use strict;
use warnings;

my %member_info = (
   mid           => undef,
   created_info  => { created_by => undef,
                      created_date => undef,
                    },
   modified_info => { modified_by => undef,
                      modified_date => undef,
                    },
   person        => 
                    { salutation         => undef,
                      first_name         => undef,
                      middle_initial     => undef,
                    },
   school => [ { school_type     => "school",
                 school_name     => undef,
                 graduation_date => undef
               },
               { school_type     => "school1",
                 school_name     => undef,
                 graduation_date => undef
               },
             ],
          );

$member_info{'person'}{'salutation'} = "test";
$member_info{'school'}[0]{'school_type'} = "testing";
$member_info{'school'}[1]{'school_type'} = "testing2";

use Data::Dumper;

print Dumper \%member_info;

OUTPUT:
$VAR1 = {
          'mid' => undef,
          'modified_info' => {
                               'modified_date' => undef,
                               'modified_by' => undef
                             },
          'created_info' => {
                              'created_date' => undef,
                              'created_by' => undef
                            },
          'person' => {
                        'middle_initial' => undef,
                        'salutation' => 'test',
                        'first_name' => undef
                      },
          'school' => [
                        {
                          'graduation_date' => undef,
                          'school_name' => undef,
                          'school_type' => 'testing'
                        },
                        {
                          'graduation_date' => undef,
                          'school_name' => undef,
                          'school_type' => 'testing2'
                        }
                      ]
        };

##</code><code>##

...
school => { 0 => { school_type => undef }, 1 => { ... } },
...

##</code><code>##

s**lil*;  $*=join'',sort split q**;  s;.*;grr; &&s+(.(.)).+$2$1+; $; =
qq-$_-;s,.*,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$*,$/)