如何合並具有相同索引的數組

Question

我有如下數組

[{"2":[2]},{"9":[4,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,27,28,30,32,33,34,36,41]},{"2":[5,6,9]},{"7":[7,8]},{"9":[3]}]

有什么可能的方法來合並相同索引的值？

Answer 1

是的，可以解碼json字符串並使用array_reduce：

$arr = json_decode('[{"2":[2]},{"9":[4,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,27,28,30,32,33,34,36,41]},{"2":[5,6,9]},{"7":[7,8]},{"9":[3]}]');

$arr = array_reduce($arr, function ($carry, $item) {
    $key = key($item);

    if (isset($carry[$key])) {
        $carry[$key]->$key = array_merge($carry[$key]->$key, $item->$key);
    } else {
        $carry[$key] = $item;
    }

    return $carry;
});

echo json_encode(array_values($arr));

結果是：

[{“ 2”：[2,5,6,9]}，{“ 9”：[4,10,11,12,13,14,15,16,17,19,20,21,22,23 ，24,25,26,27,28,30,32,33,34,36,41,3]}，{“ 7”：[7,8]}]

Answer 2

<?php
$json = '[{"2":[2]},{"9":[4,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,27,28,30,32,33,34,36,41]},{"2":[5,6,9]},{"7":[7,8]},{"9":[3]}]';
$multi_array = json_decode($json, true);
$result = []; 
foreach($multi_array as $arr)
{        
    foreach($arr as $k => $v)
    { 
        $temp = isset($result[$k]) ? $result[$k] : [];
        $result[$k] = array_merge($temp, $v);
    }
}
print_r($result);

Answer 3

這是另一個選擇：

$old = json_decode('[{"2":[2]},{"9":[4,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,27,28,30,32,33,34,36,41]},{"2":[5,6,9]},{"7":[7,8]},{"9":[3]}]', true);

$new = [];
array_map(function ($arr) use (&$new) {
    $key = key($arr);

    $new[$key] = array_merge(current($arr), !empty($new[$key]) ? $new[$key] : []);
}, $old);

echo json_encode($new);

輸出：

{"2":[5,6,9,2],"9":[3,4,10,11,12,13,14,15,16,17,19,20,21,22,23,24,25,26,27,28,30,32,33,34,36,41],"7":[7,8]}