Comparing two arrays and inserting. Is there a better way?

Question

PHP

$arr = [
    0 => [
        "Alex","12"
    ],
    1 => [
        "Jon","17"
    ],
    2 => [
        "Mary","27"
    ]
];


$arr2 = [
    0 => [
        "Alex","some"
    ],
    1 => [
        "Jon","words"
    ],
    2 => [
        "Mary","any"
    ]
];



foreach($arr as $Full)
{
    foreach($arr2 as $End)
    {
        if($Full[0] == $End[0])
        {
            array_splice( $Full, 1, 0, "$End[1]" );
            break;
        }
    }
    
    $done = implode(",",$Full);
    $done .= "\n";
    echo $done;
}

We need a better way than this. And then I have a solution in the forehead and not very effective as for me ..
The result should be like this
Alex, some, 12
Jon, words, 17
Mary, any, 27

Answer 1

There is. Your option is O(n ² ).
Sort arrays by the first element of the subarray and pass through both arrays once. O(n*log(n))
Another option is to sort only one array and binary search it while traversing another array. O(n*log(n))