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.

• If ts is empty, return 0 (zero).
• If two numbers are as close to zero, consider the positive number as the closest to zero (eg. if ts contains -5 and 5, return 5).
Input:
• Temperatures are always expressed with floating point numbers ranging from -273 to 5526.
• ts is always a valid array and is never null.

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;

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 !