如何使用__set魔术方法查看指定数组NAME及处理实例中意外数组定义

Let's break down your questions with practical, easy-to-follow examples to clarify how __set works with arrays.

1. How to use __set to "view" a specified array (by its name)? #

First, a quick recap: The __set($name, $value) magic method triggers whenever you try to assign a value to an inaccessible (private/protected) or undefined class property. To "view" the array—whether its name or its contents—you can directly reference the $name parameter (which holds the array/property name) and inspect the $value (the array being assigned).

Here's a hands-on example:

class ArrayManager {
    // Private storage to keep our arrays safe
    private $storedArrays = [];

    public function __set($name, $value) {
        // Verify we're dealing with an array
        if (is_array($value)) {
            // Output the array's name and its contents
            echo "Array name: *{$name}*\n";
            echo "Array contents:\n";
            print_r($value);

            // Store the array for later use
            $this->storedArrays[$name] = $value;
        } else {
            echo "Only array values are allowed here!\n";
        }
    }
}

// Test it out
$manager = new ArrayManager();
// Assign an array to a "NAME" property (which doesn't exist publicly)
$manager->NAME = ['Alice', 'Bob', 'Charlie'];

When you run this, __set catches the assignment to $manager->NAME, prints the array's name and contents, then saves it to the private storage.

2. How to access an "unexpected" array via __set, output its name, or rename it? #

If your class ends up with a dynamically assigned array you didn't plan for, __set will still trigger when the array is first assigned (since it's an undefined property). Here's how to handle these cases:

Example 1: Detect and output the unexpected array's name #

Check if the array's name isn't in your predefined allowed list, then flag it:

class ArrayManager {
    private $storedArrays = [];
    // List of arrays we expect to receive
    private $expectedArrays = ['NAME', 'teamMembers'];

    public function __set($name, $value) {
        if (is_array($value)) {
            // Check if this is an unexpected array
            if (!in_array($name, $this->expectedArrays)) {
                echo "Unexpected array detected: *{$name}*\n";
            }
            $this->storedArrays[$name] = $value;
        }
    }
}

$manager = new ArrayManager();
// This is an unplanned array "arrayName"
$manager->arrayName = ['apple', 'banana', 'cherry'];

Example 2: Rename the submitted array #

If you want to rebrand an array from its original name to a new one, map the old name to a new key inside __set:

class ArrayManager {
    private $storedArrays = [];

    public function __set($name, $value) {
        if (is_array($value)) {
            // Rename "arrayName" to "fruitCollection"
            if ($name === 'arrayName') {
                $newArrayName = 'fruitCollection';
                echo "Renamed array from *{$name}* to *{$newArrayName}*\n";
                $this->storedArrays[$newArrayName] = $value;
            } else {
                $this->storedArrays[$name] = $value;
            }
        }
    }

    // Add __get to retrieve the renamed array later
    public function __get($name) {
        return $this->storedArrays[$name] ?? null;
    }
}

$manager = new ArrayManager();
$manager->arrayName = ['apple', 'banana'];
// Fetch the renamed array
print_r($manager->fruitCollection);

This code takes the array assigned to arrayName, renames it to fruitCollection, and lets you access it with the new name using __get.

内容的提问来源于stack exchange，提问作者Thompson007