PHP 中實現回撥函式 (php callback function)

資料來源: https://www.delftstack.com/zh-tw/howto/php/implement-a-callback-in-php/

方案01. PHP 中建立一個 callback 函式並使用 call_user_func 執行

<?php
    function testFunction() {
        echo "Testing Callback \n";
    }
    // Standard callback
    call_user_func('testFunction');
?>

方案02. PHP 中建立一個 callback 函式並使用 array_map 方法執行

<?php
    function length_callback($item) {
      return strlen($item);
    }
    $strings = ["Kevin Amayi", "Programmer", "Nairobi", "Data Science"];
    $lengths = array_map("length_callback", $strings);
    print_r($lengths);
?>

方案03. PHP 中實現多個回撥函式並使用使用者定義的函式執行它們

<?php
function name($str) {
  return $str . " Kevin";
}

function age($str) {
  return $str . " Kevin 23 ";
}

function testCallBacks($str, $format) {
  // Calling the $format callback function
  echo $format($str)."<br>";
}

// Pass "name" and "age" as callback functions to testCallBacks()
testCallBacks(" Hello", "name");
testCallBacks(" Hello", "age");
?>

方案04. PHP 中使用 static 類和 call_user_func 將 static 方法實現為 callback 函式

<?php
    // Sample Person class
    class Person {
          static function walking() {
              echo "I am moving my feet <br>";
          }
      }
    //child class extends the parent Person class
    class Student extends Person {
      static function walking() {
            echo "student is moving his/her feet <br>";
        }
    }
    // Parent class Static method callbacks
    call_user_func(array('Person', 'walking'));
    call_user_func('Person::walking');

    // Child class Static method callback
    call_user_func(array('Student', 'Student::walking'));
?>