php7新特性的理解和比较

1. Introduction

PHP 7 is a major release of the PHP programming language that brings several new features, improvements, and performance enhancements. It was released on December 3, 2015, and has quickly become one of the most popular versions of PHP among developers worldwide. In this article, we will discuss and compare some of the significant new features of PHP 7.

2. Improved Performance

2.1 Performance Boost

PHP 7 introduces significant performance improvements compared to its predecessor, PHP 5.6. The new version is said to run almost twice as fast as PHP 5.6. This boost in performance is mainly due to the new Zend Engine 3.0, which includes optimizations such as abstract syntax tree (AST) and just-in-time (JIT) compilation. These optimizations result in faster execution of PHP code, reducing response times and improving overall server efficiency.

One of the most important performance enhancements in PHP 7 is the introduction of the PHPNG (Next-Generation) engine. This engine has a more efficient memory usage, which contributes to the improved performance of PHP applications.

2.2 Scalar Type Declarations

PHP 7 introduces the ability to declare the types of function arguments and return values, known as scalar type declarations. This allows developers to specify the expected data types for parameters and return values, improving code readability and reducing potential errors. Scalar types include int, float, string, and bool. Type hints were previously only available for classes and interfaces.

function addNumbers(int $a, int $b): int {
    return $a + $b;
}

With scalar type declarations, it becomes easier to understand the intended data types for function parameters and return values, making code more reliable and maintainable.

3. Error Handling Improvements

3.1 Throwable Interface

PHP 7 introduces the Throwable interface, which is the base interface for all exceptions and errors in PHP. This means that both exceptions and errors can now be caught in the same catch block without the need for separate catch blocks for each. The Throwable interface allows for a more consistent and streamlined approach to error handling in PHP applications.

try {
    // Code that may throw an exception or error
} catch (Throwable $t) {
    // Handle exception or error
}

This change in error handling simplifies code and improves code readability by providing a unified way to handle both exceptions and errors.

3.2 Null Coalescing Operator

The null coalescing operator (??) is another useful addition in PHP 7. It provides a shorthand way to check if a variable is null and provide a default value in one line of code. This eliminates the need for lengthy ternary operators or isset checks.

$username = $_GET['username'] ?? 'Guest';

The null coalescing operator reduces the amount of code required to handle null values, making code more concise and easier to read.

4. Conclusion

PHP 7 brings significant improvements and new features to the PHP programming language. The performance boost, scalar type declarations, improved error handling, and the null coalescing operator are just some of the highlights of PHP 7. These features contribute to faster and more robust PHP applications, and they make coding in PHP more efficient and enjoyable. It is recommended for developers to upgrade to PHP 7 to take advantage of these new features and enhancements.