PHP array key-value exchange: efficient implementation and performance discussion

PHP Two efficient methods for array key-value exchange: using the array_flip() function (efficient, recommended for large amounts of data) manual exchange (relatively slow, suitable for small amounts of data) Performance tests show that the array_flip() function performs better in exchange About 2.3 times faster than manual swapping at 100,000 elements.

PHP Array Key Value Exchange: Efficient Implementation and Performance Discussion

In PHP, sometimes we need to exchange the keys of the array value. This blog post will explore two efficient implementations and compare their performance through practical cases.

Method 1: array_flip() function

$arr = ['foo' => 'bar', 'baz' => 'qux'];
$reversedArr = array_flip($arr);

Method 2: Manual exchange

$arr = ['foo' => 'bar', 'baz' => 'qux'];

$newArray = [];
foreach ($arr as $key => $value) {
    $newArray[$value] = $key;
}

Practical case

We will use PHP's microtime(true) function to measure the execution time of the two methods:

$arr = range(1, 100000); // 创建一个包含 100,000 个元素的数组

// array_flip() 方法
$startTime = microtime(true);
$reversedArr = array_flip($arr);
$endTime = microtime(true);
$timeTakenArrayFlip = $endTime - $startTime;

// 手动交换方法
$startTime = microtime(true);
$newArray = [];
foreach ($arr as $key => $value) {
    $newArray[$value] = $key;
}
$endTime = microtime(true);
$timeTakenManual = $endTime - $startTime;

Result

On my test machine, the array_flip() method took about 0.0013 seconds to perform 100,000 key-value swaps, while the manual swap method took about 0.003 seconds.

Conclusion

For key-value exchange, the array_flip() function is a more efficient method in PHP, especially when dealing with large amounts of data.

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