What are the new features of PHP?

PHP’s new features include: scalar type declaration (to improve code readability and maintainability), anonymous classes (to facilitate the creation of one-time objects), return type declaration (static analysis and to improve maintainability), space ship operator ( Compares expression values), Null coalescing operator (provides alternative values), spread operator (expands arrays/objects). These features enhance the functionality of PHP by improving code maintainability and efficiency.

Exploring New Features of PHP

PHP as a popular programming language continues to evolve, introducing new features to improve its functionality and efficiency. This article will delve into the latest features of PHP and provide practical code examples to illustrate.

1. Scalar type declaration

Introduced in PHP 7.0, scalar type declaration allows developers to specify the data type of variables, such as int, float, string, etc. This helps code readability and maintainability.

<?php
declare(strict_types=1);

// 定义一个整型变量
$age = 25;
// 定义一个字符串变量
$name = 'John Doe';

2. Anonymous classes

PHP 7.0 also introduces anonymous classes, which allow a class to be defined and used directly without explicitly specifying its name. This is useful for creating disposable objects or implementing callback functions.

<?php
// 创建一个匿名类
$object = new class {
    public function sayHello() {
        echo 'Hello, world!';
    }
};

// 调用类的方法
$object->sayHello();

3. Return type declaration

PHP 7.0 also supports return type declaration, which allows developers to specify the return value type of a function or method. This helps with static analysis and improves code maintainability.

<?php
// 定义一个函数，返回一个整型
function sum(int $a, int $b): int {
    return $a + $b;
}

echo sum(1, 2); // 输出 3

4. Space ship operator

The space ship operator () was introduced in PHP 7.0. It Compares the values ​​of two expressions and returns an integer representing the result of the comparison.

<?php
$result = 1 <=> 2; // -1
$result = 2 <=> 2; // 0
$result = 3 <=> 2; // 1

5. Null coalescing operator

The Null coalescing operator (??) was introduced in PHP 7.0, which provides Convenience method for using a substitute value when a variable is null.

<?php
$name = $_GET['name'] ?? 'Guest';

6. Extension operator

The extension operator (...) was introduced in PHP 7.4, which allows arrays to be or object expansion into function or method calls.

<?php
$numbers = [1, 2, 3];
echo implode(',', ...$numbers); // 输出 1,2,3

Practical Case: Building a Calculator

The following is a simple PHP calculator example that demonstrates some of the new features mentioned above:

<?php
// 使用标量类型声明定义变量
declare(strict_types=1);

$firstNumber = floatval($_GET['firstNumber'] ?? 0);
$secondNumber = floatval($_GET['secondNumber'] ?? 0);
$operation = $_GET['operation'] ?? 'sum';

// 使用空间船操作符比较操作
switch ($operation) {
    case 'sum':
        $result = $firstNumber + $secondNumber;
        break;
    case 'subtract':
        $result = $firstNumber - $secondNumber;
        break;
    case 'multiply':
        $result = $firstNumber * $secondNumber;
        break;
    case 'divide':
        // 处理除数为零的情况
        $result = $secondNumber === 0 ? null : $firstNumber / $secondNumber;
        break;
    default:
        $result = null;
}

// 使用 null 合并运算符提供默认值
echo $result ?? 'Invalid operation';

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