How to use code refactoring techniques to improve PHP function performance?

Code refactoring is an effective technique to improve the performance of PHP functions. It optimizes the code structure and reduces duplication through inline variables, extraction methods, use of lookup tables, etc., including: 1. Inline variables: Eliminate variable creation and destruction overhead. 2. Extraction method: Improve code readability and maintainability. 3. Use a lookup table: speed up constant value lookup.

How to use code refactoring technology to improve PHP function performance

Code refactoring is an important technology to improve PHP code performance. This is achieved by optimizing function structures and reducing duplication. Here are some common code refactoring techniques:

Inline variables

Inline variables refer to embedding a variable assignment directly into the expression that requires it. This eliminates the overhead of creating and destroying variables.

// 原代码
$num = 10;
echo "The number is $num";

// 内联后代码
echo "The number is 10";

Extraction method

Extraction method refers to extracting part of a function into a separate method. This helps improve code readability and maintainability.

// 原代码
function calculate($a, $b) {
   if ($a > $b) {
       $result = $a + $b;
   } else {
       $result = $a - $b;
   }
   return $result;
}

// 提取方法后代码
function calculate($a, $b) {
   if ($a > $b) {
       return add($a, $b);
   } else {
       return subtract($a, $b);
   }
}

function add($a, $b) {
   return $a + $b;
}

function subtract($a, $b) {
   return $a - $b;
}

Using lookup tables

Lookup tables can be used to improve the performance of functions looking for constant values. It avoids traversing large amounts of data by storing constant values ​​in arrays or hash tables.

// 原代码
function get_city_by_id($id) {
   $cities = array(
       1 => 'New York',
       2 => 'London',
       3 => 'Paris'
   );
   
   if (isset($cities[$id])) {
       return $cities[$id];
   } else {
       return null;
   }
}

// 使用查找表后代码
$cities = array(
       1 => 'New York',
       2 => 'London',
       3 => 'Paris'
   );

function get_city_by_id($id) {
   global $cities;
   return isset($cities[$id]) ? $cities[$id] : null;
}

Practical case

The following is a practical case of using code refactoring to improve the performance of PHP functions:

// 原函数
function get_average($numbers) {
   $total = 0;
   foreach ($numbers as $number) {
       $total += $number;
   }
   $average = $total / count($numbers);
   return $average;
}

// 使用代码重构优化后函数
function get_average($numbers) {
   return array_sum($numbers) / count($numbers);
}

By using the built-in array_sum() function, the optimized code eliminates the overhead of traversing the array and accumulating numbers one by one, significantly improving performance.

Code refactoring is a continuous process. By continuously optimizing the code structure, the performance and efficiency of PHP functions can be significantly improved.

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