在PHP中组合多个数组值

I have three arrays right now the values of which I want to combine together. All of the values have matching keys but I can't work out quite how to do it. To put it more visually I have:

array{
    [0] => "Foo"
}

array{
    [0] => " Bar"
}

and I want:

array{
    [0] => "Foo Bar"
}

But for the life of me I can't figure out how! At first I thought about using nested foreach statements like

$result = array();

foreach ($array1 as &$input1) {
    foreach ($array2 as &$input2) {
        $result[] = $input1 . $input2;
    }
}

But while that combined the values, it generated a lot of correct ones (The array was about twice the size as expected).

Use the keys

$output = array();

foreach (array_keys($array1) as $key) {
    $output[] = $array1[$key] . $array2[$key]; // and possibly . $array3[$key]
}