The Art of PHP Array Deep Copy: Using Different Methods to Achieve a Perfect Copy

Methods for deep copying arrays in PHP include: using json_decode and json_encode for JSON encoding and decoding. Use array_map and clone to make deep copies of keys and values. Use serialize and unserialize for serialization and deserialization.

The Art of PHP Array Deep Copy: Using Different Methods to Achieve Perfect Copy

In PHP, array is a powerful data Structures used to store and manage related data. Sometimes we need to create a copy of an array to perform operations or to avoid accidental modifications to its original data. This is where deep copy comes into play: it creates a new array containing all the elements of the original array, including nested arrays and objects.

Method 1: json_decode and json_encode

<?php
$originalArray = [
    'name' => 'John Doe',
    'age' => 30,
    'hobbies' => ['reading', 'hiking', 'coding']
];

// JSON 编码原始数组
$jsonEncoded = json_encode($originalArray);

// JSON 解码 JSON 编码的字符串
$deepCopy = json_decode($jsonEncoded, true);

print_r($deepCopy);
?>

Method 2: array_map and clone

<?php
$originalArray = [
    'name' => 'Jane Smith',
    'age' => 25,
    'address' => ['street' => 'Main Street', 'number' => 123]
];

// 复制数组键及其值的深度副本
$deepCopy = array_map(function($value) {
    return is_array($value) ? array_map('clone', $value) : clone $value;
}, $originalArray);

print_r($deepCopy);
?>

Method 3: serialize and unserialize

<?php
$originalArray = [
    'product' => 'Book',
    'quantity' => 5,
    'details' => ['author' => 'John Smith', 'publisher' => 'ACME Press']
];

// 序列化原始数组
$serialized = serialize($originalArray);

// 反序列化序列化字符串
$deepCopy = unserialize($serialized);

print_r($deepCopy);
?>

Practical Case: Shopping Cart Manager

Consider a shopping cart manager that manages the items in the user's shopping basket. To avoid modifying the original basket, we need to create a copy of it to perform operations such as calculating the total price or removing items. Deep copying ensures that we have an independent copy that does not affect the original basket.

<?php
// 原始购物篮数组
$originalCart = [
    ['product' => 'Book', 'quantity' => 3],
    ['product' => 'Pen', 'quantity' => 2],
    ['product' => 'Charger', 'quantity' => 1]
];

// 使用方法 1 创建购物篮副本
$deepCopy = json_decode(json_encode($originalCart), true);

// 在副本中移除一个商品
unset($deepCopy[1]);

// 输出更新后的购物篮副本
print_r($deepCopy);
?>

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