获取具有不同数组的字段的最低值

Question

I have created the following array in PHP with help of the Google Distance Matrix API.

Now I need to compare the [distance] field, get the lowest value and save the key of the array in a variable. How do I do this? I looked at min() but this doesn't seem to work with multiple arrays.

Array
(
[utrecht_cs] => Array
    (
        [name] => utrecht_cs
        [address] => 3511 AX Utrecht, Netherlands
        [distance] => 95
    )

[groningen_cs] => Array
    (
        [name] => groningen_cs
        [address] => 9726 AC Groningen, Netherlands
        [distance] => 102.47
    )

[zwolle_cs] => Array
    (
        [name] => zwolle_cs
        [address] => 8011 CW Zwolle, Netherlands
        [distance] => 2.54
    )

)

Answer 1

You could use uasort() to sort your array. Then, you could get the first key using key().

$array = array(
    'utrecht_cs' => array(
        'name' => 'utrecht_cs',
        'address' => '3511 AX Utrecht, Netherlands',
        'distance' => 95
    ),
    'groningen_cs' => array(
        'name' => 'groningen_cs',
        'address' => '9726 AC Groningen, Netherlands',
        'distance' => '102.47'
    ),
    'zwolle_cs' => array(
        'name' => 'zwolle_cs',
        'address' => '8011 CW Zwolle, Netherlands',
        'distance' => '2.54'
    )
);

uasort($array, function($a, $b) { return $a['distance'] <=> $b['distance']; });
$first_key = key($array);

Output:

zwolle_cs

You can also use (for PHP version before 7.0):

uasort($array, function($a, $b) { 
   return $a['distance'] < $b['distance'] ? -1 : 1; 
});