shuffle() 不能按预期使用关联数组

Question

我想做一个测验，这是我的数组：

$questions = array("1+1"=>2,"5+2"=>7,"5+9"=>14,"3+5"=>8,"4+6"=>10,"1+8"=>9,"2+7"=>9,
                   "6+7"=>13,"9+3"=>12,"8+2"=>10,"5+5"=>10,"6+8"=>14,"9+4"=>13,"7+8"=>15,
                   "8+9"=>17,"4+8"=>12,"7+1"=>8,"6+3"=>9,"2+5"=>7,"3+4"=>7);

shuffle($questions);

foreach($questions as $key => $value) {
     echo $key.' ';
}

但是，从上面的代码中，我得到如下输出：

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 //Wrong!

为什么我会得到这个输出？我想得到每一个问题。我该如何获取？

Answer 1

来自 shuffle() 的手册（强调我的）：

Note: This function assigns new keys to the elements in array. It will remove any existing keys that may have been assigned, rather than just reordering the keys.

这是来自该页面 comments 的关联数组的解决方案：

function shuffle_assoc(&$array) {
    $keys = array_keys($array);

    shuffle($keys);

    foreach($keys as $key) {
        $new[$key] = $array[$key];
    }

    $array = $new;

    return true;
}

_{致谢名单："ahmad at ahmadnassri dot com"}

Answer 2

¿shuffle 关联数组？这对我有用：

 function shuffle_assoc($array) {
    $keys = array_keys($array);
    shuffle($keys);
    foreach($keys as $key) {
        $new[$key] = $array[$key];
    }
    return $new;
}

使用：

Print_r(shuffle_assoc($my_array));

输入：

$my_array = Array
                (
                  [Nicaragua] => 62
                  [Mexico] => 50
                  [France] => 23
                 )

输出：

Array
(
    [France] => 23
    [Nicaragua] => 62
    [Mexico] => 50
)

shuffle() 不能按预期使用关联数组

shuffle() doesn't work as expected with an associative array

php

arrays

associative-array

shuffle