php - 在数组中搜索最接近 0 的负值和正值

Question

我需要在数组中找到最接近零的负值和正值。

• 如果数组为空，我们返回 0。
• 如果数组有例如 -7, 7，我们返回 7。

这是正确的做法吗？

$ts = [1.7, 7, -10, 13, 8.4, -7.2, -12, -3.7, 3.5, -9.6, 6.5, -1.7, -6.2, 7];

function closestToZero (array $ts)
{
    if(empty($ts)){

        return 0;
    }

    $negativeArr = [];
    $postiveValue = [];

    foreach ($ts as $number) {
        if ($number < 0) {
            $negativeArr[] = $number;
        }elseif ($number > 0 ) {

            $postiveValue[] = $number;
        }
    }

    if(!empty($negativeArr)){

        $minnegative = max($negativeArr);
    }

    if (!empty($postiveValue)) {
        $minPositive = min($postiveValue);
    }
    if ((abs($minnegative) - $minPositive) == 0) {

        return $minPositive;
    }else{
        return $minnegative.' '.$minPositive;
    }



}

echo "结果是 ".closestToZero($ts);

编辑:

我实际上是在寻找一种优化的方法，经过一些研究我最终发现这个女巫更加优化

    //if the array is empty we do nothing we return
if(empty($ts)){

    return 0;
}else{

    $referenceValue = 0;

    //the trick is to add the reference value to the array if it doesnt exist
    if (in_array($referenceValue, $ts) === FALSE) {
        array_push($ts, $referenceValue);
    }

    //we sort the array in an ascending order
    sort($ts);

    // now we are able to get the nearest postive and negative values from 0
    $referenceValueKey = array_search($referenceValue, $ts);

    $positiveValueKey = $referenceValueKey + 1;
    $negativeValueKey = $referenceValueKey - 1;

    $result = '';
    // if there is the same number as negative and positive in the array, we return the positive one
    if((abs($ts[$negativeValueKey]) - $ts[$positiveValueKey]) == 0 )
    {
        $result.= $ts[$positiveValueKey];

    }else{

        $result.= $ts[$negativeValueKey].' '.$ts[$positiveValueKey];
    }

    return $result;



}






}

Answer 1

你可以用更少的代码来做到这一点:

<?php

function getClosest(array $x)
{
    // put them in order first
    sort($x);

    $results = [];

    foreach($x as $y) {
        if ($y < 0) {
            $results['-'] = $y; // next negative is closer to 0
        } else {
            $results['+'] = $y; // first positive is closest to 0
            return $results;
        }
    }
    return count($results) > 0 ? $results : 0;
}

$x = [1.7, 7, -10, 13, 8.4, -7.2, -12, -3.7, 3.5, -9.6, 6.5, -1.7, -6.2, 7];

$y = getClosest($x);
var_dump($y);

哪个返回:

array(2) { ["-"]=> float(-1.7) ["+"]=> float(1.7) }