php find max value for both positive and negative value in array

Question

I have an array i want to find max value for both positive and negative value. The expected result would be -13.2 and 7.8

$array = array
(
 [0] => -13.2
 [1] => -14.5
 [2] => -14.3
 [3] => -13.7
 [4] => -13.8
 [5] => -14.6
 [6] => 6.4
 [7] => 6.9
 [8] => 7.2
 [9] => 6.9
 [10] => 7.8
 [11] => 6.9
 [12] => 6.3
 [13] => 7.2
 [14] => 6.9
 [15] => 6.8
)
$maxrl='';
for($i=1,$j=0;$i<=count($array);$i++,$j++)
 {
 if($maxr <= $array[$j])
 {
 if(($maxr < $array[$j]) && ($maxrl != ''))
 {
 $maxrl='';
 $maxrl.="L".$k.",";
 }
 else
 {
 $maxrl.="L".$k.",";
 }
 $maxr = $max_array[$j];
 }
 $k++;
 }
echo "<tr><td >'.$maxr.'</td><td>'.substr($maxrl,0,-1).'</td><>/tr>";

• Axel Amthor: "The maximum for a negative value" usual is called "minimum" ...
• Shankar Narayana Damodaran: It should return -14.6 not -13.2
• Mark Baker: Do you mean the highest negative value, or the lowest? $maxNegative = max(array_filter($myArray, function($value){return $value<0;}));
• Barmar: @ShankarDamodaran \ I think he wants the highest negative value, that's why the expected answer is -13.2.
• Axel Amthor: If the OP wants -13.2 as a result, that would mean the maximum of the negative values. And then just min($array) won't work. One needs to split the array in positive and negative values and get the max from the negative ones.

Answer 1

You can simply use max & min functions,

echo "Max Value:- ".max($array); // Max Value:- 7.8
echo "Min Value:- ".min($array); // Min Value:- -14.6

UPDATED: If you really want max from both negative & positive values,

$positive = array_filter($array, function ($v) {
 return $v > 0;
});
$negative = array_filter($array, function ($v) {
 return $v < 0;
});
echo "Max in positive Value:- ".max($positive); // Max in positive Value:- 7.8
echo "Min in negative Value:- ".min($negative); // Max in negative Value:- -13.2

• Shankar Narayana Damodaran: -14.6 actually ;)
• Rikesh: @ShankarDamodaran - Corrected. sharp eyes :)
• Barmar: But the answer he wants for the negatives is -13.2, the maximum negative number.
• Rikesh: @Barmar - Totally agree with you,was just updating my answer.
• Rikesh: Shankar - Thanks. We all just miss-understood the question on first look. Thanks to @Barmar :)

Answer 2

For the positive maximum just take

$max = max($array);

The highest minimum is a bit more complex:

$minArray = array();
foreach ( $array as $val )
 if ( $val < 0 )
 $minArray[] = $val;
$min = max($minArray);

If I get the OPs question right

Answer 3

PHP has max and min methods specifically for this

$max = max($array); // 7.8
$min = min($array); // -14.6

Answer 4

//$dd = array(-50, -25, -5, -80, -40, -152, -45, -28, -455, -100, -98, -455);
$dd = array(50, -25, -5, 80, -40, -152, -45, 28, -455, 100, 98, -455);
//$dd = array(50, 25, 5, 80, 40, 152, 45, 28, 455, 100, 98, 455);
$curr = '';
$max = $dd[0];
for($i = 0; $i < count($dd); $i++) {
 $curr = $dd[$i];
 if($curr >= $max) {
 $max = $curr; 
 }
}
echo "greatest number is $max";

Answer 5

Just do:

$max = max($array);
$min = min($array);

Much easier! ;)

• Thomas Hansen: Why the -1? This is the standard way of doing it!