Question

I have an array like this:

array (0 => 
  array (
    'id' => '20110209172713',
    'Date' => '2011-02-09',
    'Weight' => '200',
  ),
  1 => 
  array (
    'id' => '20110209172747',
    'Date' => '2011-02-09',
    'Weight' => '180',
  ),
  2 => 
  array (
    'id' => '20110209172827',
    'Date' => '2011-02-09',
    'Weight' => '175',
  ),
  3 => 
  array (
    'id' => '20110211204433',
    'Date' => '2011-02-11',
    'Weight' => '195',
  ),
)

I need to extract minimal and maximal Weight values.
In this example

$min_value = 175

$max_value = 200

Any help on how to do this ?
Thank you !

Answer 1

Option 1. First you map the array to get those numbers (and not the full details):

$numbers = array_column($array, 'weight')

Then you get the min and max:

$min = min($numbers);
$max = max($numbers);

Option 2. (Only if you don’t have PHP 5.5 or better) The same as option 1, but to pluck the values, use array_map:

$numbers = array_map(function($details) {
  return $details['Weight'];
}, $array);

Option 3.

Option 4. If you only need a min OR max, array_reduce() might be faster:

$min = array_reduce($array, function($min, $details) {
  return min($min, $details['weight']);
}, PHP_INT_MAX);

This does more min()s, but they’re very fast. The PHP_INT_MAX is to start with a high, and get lower and lower. You could do the same for $max, but you’d start at 0, or -PHP_INT_MAX.