根据数组值之间的变量值查找数组的键

Question

我需要找到对应于变量值的基本数组的 left-near 键。

搜索值（在这种情况下）始终介于 1 和 779 之间

举个例子更好：

$fixedArr = [ 0, 5, 8, 20, 40, 60, 90, 135, 780 ];

$search = 42; // $result = $arr[4] -> 4;
$search = 110; // $result = $arr[6] -> 6;

$search = 134; // $result = $arr[6] -> 6;
$search = 135; // $result = $arr[7] -> 7;

我尝试使用 foreach 循环，但没有运气，知道吗？ 谢谢

Answer 1

搜索值始终介于（在这种情况下）1 和 779

$fixedArr = [ 0, 5, 8, 20, 40, 60, 90, 135, 780 ];

$search = 42;
for ($i = 0; $i < count($fixedArr); $i++) 
   if ($search < $fixedArr[$i]) break;

echo $i-1;

Answer 2

这也许对你有帮助；

$fixedArr = [ 0, 5, 8, 20, 40, 60, 90,135,780 ];
//
$search = 111; // $result = $arr[4] -> 4;
//$search = 110; // $result = $arr[6] -> 6;
//
function leftORright($fixedArr,$search){
    $max = max($fixedArr)+1;
    $near = array(
    'left'=>array('key'=>'none','value'=>'none','bool'=>false),
    'right'=>array('key'=>'none','value'=>$max,'bool'=>false),
    'center'=>array('key'=>'none','value'=>'none','bool'=>false)
    );
    foreach($fixedArr as $k=>$v){
        if($v == $search){
            $near['center']['key'] = $k;
            $near['center']['value'] = $v;
        }
        if($v < $search){
            $near['left']['key'] = $k;
            $near['left']['value'] = $v;
        }
        if($v > $search and $near['right']['value'] > $v){
            $near['right']['key'] = $k;
            $near['right']['value'] = $v;
        }
    }
    //decide near left or right
    $respright = $near['right']['value'] - $search;
    $respleft = $search - $near['left']['value'] ;
    $right_left_equals = false;
    if($near['center']['value'] !== 'none'){
        $near['center']['bool'] = true;
    }else if($respleft < $respright && $near['left']['key']!='none'){
        $near['left']['bool'] = true;
    }else if($respleft > $respright && $near['right']['key']!='none'){
        $near['right']['bool'] = true;
    }else if($near['center']['value'] != 'none'){
        $near['center']['value'] = true;
    }else{
        $right_left_equals = true;
    }
    //var_dump($near);
    //Result is:
    foreach($near as $k=>$v){
        foreach($v as $k2=>$v2){
            if($v2===true){
                var_dump('near is for '.$k);
                return $v;
            }
        }
    }
    //equal for right and left
    if($right_left_equals){
        var_dump('near right left are equals');
        return array($near['right'],$near['left']);
    }
}
$result = leftORright($fixedArr,$search);
var_dump($result);

回复：

string 'near is for left' (length=16)

array (size=3)
  'key' => int 6
  'value' => int 90
  'bool' => boolean true

Answer 3

使用array_search:

array_search — 在数组中搜索给定的值，如果成功则返回相应的键

$search = array_search(42, $fixedArr); // -> 4
$search = array_search(110, $fixedArr); // -> 6

您的问题类似于寻找最接近的问题：

<?php
    $fixedArr = [ 0, 5, 8, 20, 40, 60, 90, 135, 780 ];
    function getClosest($search, $arr) {
        $left = 0;
        foreach ($arr as $val) {
            if ($search > $val)
                $left = $val;
            elseif ($search < $val) {
                $right = $val;
                break;
            }
            else {
                $right = $val;
                break;
            }
        }
        return array($left, $right, array_search($left, $arr), array_search($right, $arr), (($search - $left) > ($right - $search) ? array_search($right, $arr) : array_search($left, $arr)));
    }
    print_r(getClosest(4, $fixedArr));
?>

Answer 4

试试这个：它适用于所有情况。

$fixedArr = [ 0, 5, 8, 20, 40, 60, 90, 135, 780 ];
$find = 14;
for ($i=0; $i < count($fixedArr); $i++) {
    if($fixedArr[$i] <= $find){
        $large[] = $fixedArr[$i];       
    }else{
        $small[] = $fixedArr[$i];
    }
}
$near1 = max($large);
$near2 = min($small);
echo "Value $find coming in between $near1 and $near2";
echo "<br>";
if($find >= ($near1 + $near2) / 2){
    echo "Closed Value is : $near2";
}else{
    echo "Closed Value is : $near1";
}

输出：

Value 14 coming in between 8 and 20
Closed Value is : 20