PHP array key-value exchange: Algorithm and performance analysis of sequential key-value exchange

PHP There are two algorithms for array key-value exchange: simple key-value exchange and sequential key-value exchange. The former traverses the array and stores the key values ​​into a new array in one-to-one correspondence, while the latter uses the array_values() and array_keys() functions to exchange key values ​​in order. Performance testing shows that the sequential key-value swap algorithm is significantly faster than the simple key-value swap algorithm when the array is large.

PHP Array Key Value Exchange: Algorithm and Performance Analysis of Sequential Key Value Exchange

In PHP, array is a kind of storage and management An ordered collection of data. Sometimes, we need to exchange the key values ​​of the array, which can be achieved through the following algorithm:

Simple key value exchange algorithm

function swapArrayKeysValues(array $array): array
{
    $flippedArray = [];
    foreach ($array as $key => $value) {
        $flippedArray[$value] = $key;
    }
    return $flippedArray;
}

Sequential key value exchange algorithm

In order to perform key value exchange in the order of array key values, we can use the following algorithm:

function orderedSwapArrayKeysValues(array $array): array
{
    $values = array_values($array);
    $keys = array_keys($array);
    return array_combine($values, $keys);
}

Performance analysis

In order to compare the performance of the two algorithms, we compare an array containing 10,000 An array of elements was benchmarked:

$array = range(1, 10000);

// 简单键值互换
$start = microtime(true);
$result = swapArrayKeysValues($array);
$end = microtime(true);
echo "简单键值互换耗时：" . ($end - $start) . " 秒\n";

// 按序键值互换
$start = microtime(true);
$result = orderedSwapArrayKeysValues($array);
$end = microtime(true);
echo "按序键值互换耗时：" . ($end - $start) . " 秒\n";

Output:

简单键值互换耗时：0.034162014007568 秒
按序键值互换耗时：0.0016639256477356 秒

Performance analysis shows that the sequential key-value swap algorithm is significantly faster than the simple key-value swap algorithm.

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