<?php

// 連想配列

$ary_person = [

'name' => 'suzutuki',

'weight' => '55kg',

'height' => '179cm'

];

echo $ary_person['height'];

echo('<br>');

var_dump($ary_person);

?>

179cm
array(3) { ["name"]=> string(8) "suzutuki" ["weight"]=> string(4) "55kg" ["height"]=> string(5) "179cm" }

<?php

// 連想配列

$ary_member = [

  'sun_group' => [

  'suzutuki' => [

  'weight' => '55kg',
 
  'height' => '179cm'

],
  
  'akatuki' => [

  'weight' => '70kg',

  'height' => '183cm'

],

],

  'moon_group' => [

  'akina' => [

  'weight' => '45kg',

  'height' => '149cm'

],

  'kotaro' => [

  'weight' => '60kg',

  'height' => '175m'

]

]

];
// moon_groupのakinaのweightを出力
echo$ary_member['moon_group']['akina']['weight'];

// 見やすくする

echo'<pre>';

//ary_memberのすべてを出力する
var_dump($ary_member);

echo'<pre>';

?>

45kg
array(2) {
  ["sun_group"]=>
  array(2) {
    ["suzutuki"]=>
    array(2) {
      ["weight"]=>
      string(4) "55kg"
      ["height"]=>
      string(5) "179cm"
    }
    ["akatuki"]=>
    array(2) {
      ["weight"]=>
      string(4) "70kg"
      ["height"]=>
      string(5) "183cm"
    }
  }
  ["moon_group"]=>
  array(2) {
    ["akina"]=>
    array(2) {
      ["weight"]=>
      string(4) "45kg"
      ["height"]=>
      string(5) "149cm"
    }
    ["kotaro"]=>
    array(2) {
      ["weight"]=>
      string(4) "60kg"
      ["height"]=>
      string(4) "175m"
    }
  }
}