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Which is faster, array_change_key_case() or manual traversal? Comparison of efficiency of key name case conversion
In PHP, case conversion of key names is a common requirement. Especially when processing user input or external data, the case may be inconsistent, and a unified format is required. Common practices include using the array_change_key_case() function, or manually traverse the array and modifying the case of the key names one by one. This article will compare the performance of these two methods to help developers make more appropriate choices.
PHP's built-in array_change_key_case() function is used to change the case of all key names in an array. This function accepts two parameters:
The first parameter is the array to operate on.
The second parameter is an optional flag that specifies whether to convert the key name to uppercase or lowercase. By default, the key names are converted to lowercase.
The function prototype is as follows:
array array_change_key_case ( array $array , int $case = CASE_LOWER )
If the $case parameter is set to CASE_UPPER , the key name will be converted to uppercase. Otherwise, the default is converted to lowercase.
$array = ['FirstName' => 'John', 'LastName' => 'Doe'];
$lowercaseArray = array_change_key_case($array, CASE_LOWER);
print_r($lowercaseArray);
Output:
Array
(
[firstname] => John
[lastname] => Doe
)
Another way to implement key name case conversion is to manually traverse the array and modify the case of key names one by one. This method requires using structures such as array_map() or foreach to iterate through each array element and manually adjust its key name.
$array = ['FirstName' => 'John', 'LastName' => 'Doe'];
foreach ($array as $key => $value) {
$newKey = strtolower($key); // or strtoupper($key) Convert capitalization
$newArray[$newKey] = $value;
}
print_r($newArray);
Output:
Array
(
[firstname] => John
[lastname] => Doe
)
To compare the efficiency of these two methods, we can use PHP's microtime() function to record the execution time of each method. Here is the simple performance test code:
// Prepare a larger array
$array = [];
for ($i = 0; $i < 100000; $i++) {
$array['Key' . $i] = 'Value' . $i;
}
// test array_change_key_case()
$startTime = microtime(true);
array_change_key_case($array, CASE_LOWER);
$endTime = microtime(true);
echo "array_change_key_case() Execution time: " . ($endTime - $startTime) . " Second\n";
// testManual traversal
$startTime = microtime(true);
$newArray = [];
foreach ($array as $key => $value) {
$newKey = strtolower($key); // Turn lowercase
$newArray[$newKey] = $value;
}
$endTime = microtime(true);
echo "Manual traversal Execution time: " . ($endTime - $startTime) . " Second\n";
Advantages of array_change_key_case() :
The code is concise and easy to understand.
For smaller arrays, there is little to no problem with performance.
The execution efficiency of built-in functions is usually better than manual traversal, especially when the array is large.
Advantages of manual traversal :
In some special cases, greater flexibility can be provided. For example, you may need to do other complex operations on key names while converting case.
You can precisely control the conversion method of key names (such as partial conversion of key names according to certain rules).
For most normal scenarios, array_change_key_case() is a simpler and more efficient choice. Its internal implementation is optimized and usually executes faster than manual traversal, especially when dealing with large arrays. However, in special scenarios where key names need to be handled more flexibly, manual traversal is also a good choice.
If we consider it purely from a performance perspective, array_change_key_case() is undoubtedly a faster solution, especially when it comes to large-scale data operations. For some simple tasks, avoiding unnecessary traversal operations, using built-in functions is usually more efficient.
