我在索引中只有一个数组，所以我想将索引移动到上一个索引？ 请参阅下面的参考：

Array
(
    [data] => Array
        (
            [0] => Array
                (
                    ['degree_level'] => Bachelor's
                )

            [1] => Array
                (
                    ['field_of_study'] => Science
                )

            [2] => Array
                (
                    ['grade_point'] => 3
                )

            [3] => Array
                (
                    ['criteria'] => desired
                )

        )

)

What I want :

Array
(
    [data] => Array
        (
            ['degree_level'] => Bachelor's

            ['field_of_study'] => Science

            ['grade_point'] => 3

            ['criteria'] => desired

        )

)

$output = array_map(function($item) { return $item[0]; }, $myArray);

You should use array_flatten(); to achieve your goal like this,

$flattened = array_flatten(Your_Data_Array);

Please give it a try and let me know.

UPDATE

$flattened = array_map(function($item) {
                return $item[0];
             }, Your_Data_Array);

For more information you can visit this for PHP functions.

Let me know in case of any queries.

you can achieve this using array_collapse.

Link

EDIT :

while tag has changed.

Here is the core php solution based on Laravel array_collapse:

function collapse($array)
{
    $results = [];

    foreach ($array as $values) {
       if (! is_array($values)) {
            continue;
        }

        $results = array_merge($results, $values);
    }

    return $results;
}

Try this,

foreach($data as $key1=>$val1){
    foreach($val1 as $key2=>$val2){
        $new_array[$key2] = $val2;
        }
    }

You can do it by loop.

foreach ($data as $key => $value) {
    foreach ($value as $key1 => $value2) {
        $data[$key1] = $value2;
    }
}

You could use for example a double foreach loop to use the key and the value from the second loop and add those to the $arrays["data"] array.

Then you could use unset to remove the nested arrays.

$arrays = [
    "data" => [
        ["degree_level" => " Bachelor's"],
        ["field_of_study" => "Science"],
        ["grade_point" => 3],
        ["criteria" => "desired"]
    ]
];

foreach($arrays["data"] as $dataKey => $data) {
    foreach ($data as $key => $value) {
        $arrays["data"][$key] = $value;
    }
    unset($arrays["data"][$dataKey]);
}
print_r($arrays);

That would give you:

Array
(
    [data] => Array
        (
            [degree_level] =>  Bachelor's
            [field_of_study] => Science
            [grade_point] => 3
            [criteria] => desired
        )

)

Demo