How to gradually update your code to be compatible with PHP7.4

Title: How to gradually update your code to be compatible with PHP 7.4

Introduction:
As technology continues to develop, programming languages ​​are constantly being upgraded and improved. . In order to keep up with the latest technology trends and improve the performance and security of the code, it is very important to update the code in a timely manner. This article will walk you through how to update your code to be compatible with PHP 7.4, along with some code examples.

1. Understand the new features of PHP 7.4
Before starting to update the code, you should first understand the new features and improvements of PHP 7.4. PHP 7.4 brings some important changes, including new syntax, new functions and performance optimizations. Here are some features worth noting:

1. Typed Properties
   PHP 7.4 introduced support for property types, allowing the type of properties to be declared in a class. This improves code readability and security. For example:

class Person {
   public string $name;
   public int $age;
}

2. Arrow Functions
   Arrow functions are another important feature of PHP 7.4, which provide a more concise syntax to define anonymous functions. For example:

$numbers = [1, 2, 3, 4, 5];
$squares = array_map(fn($n) => $n * $n, $numbers);

3. Preloading
   PHP 7.4 introduces a preloading mechanism that can preload commonly used PHP files into memory to improve performance. This is a very useful feature for large projects or frameworks.

2. Update PHP version and check for warnings and errors

1. Upgrade PHP version
   First, upgrade your PHP version to PHP 7.4 or higher. Make sure your server or development environment supports PHP 7.4.
2. Run the test suite
   Run the test suite in your code base to catch possible warnings and errors. PHP 7.4 brings changes to some old syntax and functions that may cause problems with existing code.

3. Gradually update and repair the code

1. Update by functional module
   According to the structure of your code base, divide the functional modules into multiple parts, one by one Partially updated. This reduces risk across the codebase and makes it easier to locate and resolve issues.
2. Handling obsolete functions and syntax
   Find obsolete functions and syntax used in your code and modify them. For example, PHP 7.4 has deprecated some functions and syntax, such as: no longer need to use parentheses after instantiating the keyword new, no longer need to use array() when creating an array, etc. .
3. Add attribute type declarations
   Add type declarations to your class attributes to improve code readability and maintainability. Not only will this help you catch potential errors earlier, but it will also provide your IDE with better code hints.
4. Refactor anonymous function
   Replace the original anonymous function using create_function() with an arrow function to provide cleaner and more readable code. This is useful for some callback functions or simple processing logic.
5. Use the preloading function
   For projects with higher performance requirements, you can try to use the preloading function of PHP 7.4. Preloading can greatly improve the performance of a project, especially when the project contains a large number of dependencies and custom classes.

Conclusion:
By gradually updating and fixing the code, we can make the code base compatible with PHP 7.4 and enjoy the performance and security benefits at the same time. Before updating your code, it's important to understand the new features and run the test suite. At the same time, we also provide some code examples of common update operations, which we hope will be helpful to your update work. Remember, keeping your code updated is key to staying competitive, while also helping to improve your development process and code quality.

The above is the detailed content of How to gradually update your code to be compatible with PHP7.4. For more information, please follow other related articles on the PHP Chinese website!