How to find the closest value to zero from an array with positive and negative numbers in PHP

On the last days, i needed to fill a codingame test that exposed the following problem that needed to be solved:

In this exercise, you have to analyze records of temperature to find the closest to zero. Sample temperatures. Here, -1.7 is the closest to 0. Implement the function closestToZero to return the temperature closer to zero which belongs to the array ts.

Solution

Based on the exposed data, the following implementation solves the problem:

<?php

/**
 * From a collection of numbers inside an array, returns the closest value to zero.
 */
function computeClosestToZero(array $ts) {
    if(empty($ts)){
        return 0;
    }
    
    $closest = 0;
    
    for ($i = 0; $i < count($ts) ; $i++) {
        if ($closest === 0) {
            $closest = $ts[$i];
        } else if ($ts[$i] > 0 && $ts[$i] <= abs($closest)) {
            $closest = $ts[$i];
        } else if ($ts[$i] < 0 && -$ts[$i] < abs($closest)) {
            $closest = $ts[$i];
        }
    }
    
    return $closest;
}

You can test the code with different examples of your own:

$ts = [7,-10, 13, 8, 4, -7.2,-12,-3.7,3.5,-9.6, 6.5,-1.7, -6.2,7];
// Result: -1.7
echo "Result: " . computeClosestToZero($ts);

$ts = [5, 6, 7, 9 , 2, - 2];
// Result: 2
echo "Result: " . computeClosestToZero($ts);

$ts = [];
// Result: 0
echo "Result: " . computeClosestToZero($ts);

Alternatively, one of the solutions of the community includes as well this other option:

<?php

function closestToZero(array $ts)
{
    if (count($ts) === 0) return 0;
    
    $closest = $ts[0];

    foreach ($ts as $d) 
    {
        $absD = abs($d);
        $absClosest = abs($closest);
        if ($absD < $absClosest) 
        {
            $closest = $d;
        } 
        else if ($absD === $absClosest && $closest < 0) 
        {
            $closest = $d;
        }
    }
    
    return $closest;
}

Happy coding !