如何随机遍历PHP中嵌套关联数组的第一层？

Question

I have a nested assocative array which might look something like this:

$myarray = array(
  ['tiger'] => array(
    ['people'], ['apes'], ['birds']
  ),
  ['eagle'] => array(
    ['rodents'] => array(['mice'], ['squirrel'])
  ),
  ['shark'] => ['seals']
);

How can I loop through the first layer (tiger, eagle, shark) in a random order and ensure that I cover them all in my loop? I was looking at the PHP function shuffle();, but I think that function messes up the whole array by shuffling all layers.

Answer 1

You can randomly sort an array like this, it will keep the keys and the values

<?php
$myarray = array(
  'tiger' => array(
    'people', 'apes', 'birds'
  ),
  'eagle' => array(
    'rodents' => array('mice', 'squirrel')
  ),
  'shark' => 'seals'
);

$shuffleKeys = array_keys($myarray);
shuffle($shuffleKeys);
$newArray = array();
foreach($shuffleKeys as $key) {
    $newArray[$key] = $myarray[$key];
}

print_r($newArray);

Answer 2

You can get the keys using array_keys() . Then you can shuffle the resulting key array using shuffle() and iterate through it.

Example:

$keys = array_keys($myarray);
shuffle($keys);
foreach ($keys as $key) {
  var_dump($myarray[$key]);
}

Answer 3

According to my test, shuffle only randomizes 1 layer. try it yourself:

<?php
$test = array(
        array(1,2,3,4,5),
        array('a','b','c','d','e'),
        array('one','two','three','four','five')
    );
shuffle($test);
var_dump($test);
?>