Get min and max value in PHP Array
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 !
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 $max
, but you'd start at 0
, or -PHP_INT_MAX
.
foreach ($array as $k => $v) {
$tArray[$k] = $v['Weight'];
}
$min_value = min($tArray);
$max_value = max($tArray);
For the people using PHP 5.5+ this can be done a lot easier with array_column. Not need for those ugly array_maps anymore.
How to get a max value:
$highest_weight = max(array_column($details, 'Weight'));
How to get the min value
$lowest_weight = min(array_column($details, 'Weight'));
It is interesting to note that both the solutions above use extra storage in form of arrays (first one two of them and second one uses one array) and then you find min and max using "extra storage" array. While that may be acceptable in real programming world (who gives a two bit about "extra" storage?) it would have got you a "C" in programming 101.
The problem of finding min and max can easily be solved with just two extra memory slots
$first = intval($input[0]['Weight']);
$min = $first ;
$max = $first ;
foreach($input as $data) {
$weight = intval($data['Weight']);
if($weight <= $min ) {
$min = $weight ;
}
if($weight > $max ) {
$max = $weight ;
}
}
echo " min = $min and max = $max \n " ;
How about without using predefined function like min
or max
?
$arr = [4,5,6,7,8,2,9,1];
$val = $arr[0];
$n = count($arr);
for($i=1;$i<$n;$i++) {
if($val<$arr[$i]) {
$val = $val;
} else {
$val = $arr[$i];
}
}
print($val);
?>