Remove the first level index from array php

Question

I have an array from which I want to remove the first level index and retain the value of it.
Is it possible to do without loops?

Input Array:

Array (
    [0] => Array(
             [2135] => Array(
                         [id] => 2135
                         [first_name] => John
                         [last_name] => Doe
                       )
            ),
    [1] => Array (
             [3245] => Array(
                         [id] => 3245
                         [first_name] => Sally
                         [last_name] => Smith
                       )
            )
)

Expected Output:

Array (
     [2135] => Array(
                 [id] => 2135
                 [first_name] => John
                 [last_name] => Doe
               ),


     [3245] => Array(
                 [id] => 3245
                 [first_name] => Sally
                 [last_name] => Smith
               )
)

Answer 1

Try this

$a = array (
    array(
        '2135' => array(
            'id' => 2135,
            'first_name' => 'John',
            'last_name' => 'Doe'
        )
    ),
    array (
        '3245' => array(
            'id' => 3245,
            'first_name' => 'Sally',
            'last_name' => 'Smith',
        )
    )
);
$reduce = function ($new = array(), $x) {
    $new[array_keys($x)[0]]=array_values($x)[0];
    return $new;
};

$output = array_reduce($a, $reduce);

// var_dump($output);

Answer 2

Short (commented) answer:

<?php
// simulate array
$arr = [['2135' => ['id' => 2135,'first_name' => 'John','last_name' => 'Doe']],
        ['3245' => ['id' => 3245,'first_name' => 'Sally','last_name' => 'Smith']]];

// new indexed array
$newArr = [];

array_filter($arr, function($val) {     // array_filter checks if are arrays, 
    global $newArr;                     // then use its index as key to its val.
    return !is_array($val) ?: $newArr[key($val)] = $val[key($val)];
    });

echo '<pre>';
print_r($newArr);

// You could respect your data struct and use 'id' field to name keys as well.

Output:

Array
(
    [2135] => Array
        (
            [id] => 2135
            [first_name] => John
            [last_name] => Doe
        )

    [3245] => Array
        (
            [id] => 3245
            [first_name] => Sally
            [last_name] => Smith
        )

)

Answer 3

Without loops would be difficult but possible Solution with the loops would be:

$file_array = array();
foreach($array_name as $row =>$value){
    foreach ($value as $row1 =>$value1){
        if(in_array($value1, $file_array)){
        }
        else{
        $file_array[] =$value1;
        }
    }
}