Question

我有一个这样的数组：

$pricing = array(
                 "2" => 8.23,
                 "5" => 10.97,
                 "10" => 13.28,
                 "15" => 15.40,
                 "20" => 18.15,
                 "25" => 20.36,
                 "30" => 22.84,
                 "40" => 25.60,
                 "50" => 28.35,
                 "60" => 31.89,
                 "70" => 36.23,
                 "80" => 39.40,
                 "90" => 42.52,
                 "100" => 44.75
                );

我有一个变量，其客户端的值为1到100。

问题是：如果密钥本身不存在，找到下一个最大密钥的最佳和最快方法是什么？

E.g。我有一个值为12的变量，我需要得到它的价格。根据这里的阵列，价格将是15.40，因为下一个最大的关键是15。

我可以尝试找到键号'12'，如果它不存在，我会添加一个（12 + 1）并再试一次，直到找到下一个键，但有没有任何功能可以做到这一点对我来说，还是更好/更快的东西？

编辑：澄清阵列的结构。

数组就像这里的例子一样。按键可以看到。

Answer 1

一个简单的foreach会做，但为了防止空数组或高于最高键的针，这里的实现也将覆盖它：

function find(array $pricing, $needle)
{
    $last = null; // return value if $pricing array is empty

    foreach ($pricing as $key => $value) {
        if ($key >= $needle) {
            return $key; // found it, return quickly
        }
        $last = $key; // keep the last key thus far
    }

    return $last;
}

$result = find($pricing, 12); // 15
$result = find($pricing, 101); // 100
$result = find([], 12); // null

Answer 2

假设您正在寻找'requiredKey'并且数组按键排序

这似乎可以做你想要的。

代码：

<?php

$pricing = array(
                 "2" => 8.23,
                 "5" => 10.97,
                 "10" => 13.28,
                 "15" => 15.40,
                 "20" => 18.15,
                 "25" => 20.36,
                 "30" => 22.84,
                 "40" => 25.60,
                 "50" => 28.35,
                 "60" => 31.89,
                 "70" => 36.23,
                 "80" => 39.40,
                 "90" => 42.52,
                 "100" => 44.75
                );

// What key we want...
$requiredKey =  12;

// outout in here
$foundKey   = -1;
$foundValue = -1;

// always run the loop once...
do {
    $foundKey = key($pricing);        // store the current details
    $foundValue = current($pricing);

    next($pricing); // will be equal or greater
}
while (   current($pricing) !== false
        && $foundKey < $requiredKey);


echo '<pre>';
echo '<br />', 'key: ', $foundKey, ' value: ',  $foundValue;
echo '</pre>';

输出：

key: 15 value: 15.4

Answer 3

你的逻辑没问题，你可以用next（）来做 http://php.net/manual/en/function.next.php

$search = 12;
$pricing = array(
                 "2" => 8.23,
                 "5" => 10.97,
                 "10" => 13.28,
                 "15" => 15.40,
                 "20" => 18.15,
                 "25" => 20.36,
                 "30" => 22.84,
                 "40" => 25.60,
                 "50" => 28.35,
                 "60" => 31.89,
                 "70" => 36.23,
                 "80" => 39.40,
                 "90" => 42.52,
                 "100" => 44.75
                );

$result = null;
if (!isset($pricing[$search])) {
  do {
   } while (next($pricing) && $search > key($pricing));
    $result = current($pricing);
} else {
   $result = $pricing[$search];
}

echo $result;

Answer 4

如果您从数据库获得$ price，则可以找到值数据库

PHP，如何从数组中找到下一个更大的键值

4 个答案: