php - 在预先存在的 JSON 对象中和给定的 json 对象索引之后添加空 json 对象 - Php

Question

所以我有一个从 mysql 查询生成的 JSON 对象数组。

JSON 对象看起来像:

[
  {"field1": "value1", "field2": "value2"},
  {"field1": "value3", "field2": "value4"},
  {"field1": "value5", "field2": "value6"},
  {"field1": "value7", "field2": "value8"}
]

现在我想像这样添加空对象:{} 在数组中的第 3 个 JSON 对象之后。

预期结果:

[
  {"field1": "value1", "field2": "value2"},
  {"field1": "value3", "field2": "value4"},
  {"field1": "value5", "field2": "value6"},
  {},
  {"field1": "value7", "field2": "value8"}
]

我能够遍历每个 json 对象，并且能够替换当前对象的值，但不确定如何添加一个全新的 json 空对象。

我的代码

for($j = 0; $j < $length; $j++) {

            if($j == 1 ){
                // HERE I dont want to replace Jth JSON Obj but add new empty Obj, something like $data.push('{}')
                $data[$j]['field1'] = '';
                $data[$j]['field2'] = '';
            }else{
                $data[$j]['question'] = $ques_arr[$j];
                $data[$j]['response'] = $allresponses[$j]['response'];
            }
        }

Answer 1

    $json = '[
    {"field1": "value1", "field2": "value2"},
    {"field1": "value3", "field2": "value4"},
    {"field1": "value5", "field2": "value6"},
    {"field1": "value7", "field2": "value8"}
    ]';
    $temp = json_decode($json);
    $inserted = array( (object)[]);
    array_splice( $temp, 3, 0, $inserted );
    $result = json_encode($temp);
    var_dump($result);