What are some key features introduced in PHP 7 ?
Jul 08, 2025 am 02:37 AM
PHP 7 introduced major improvements including scalar type declarations, return type declarations, the null coalescing operator, spaceship operator, anonymous classes, and performance enhancements. First, scalar type declarations allow enforcing types like int, float, bool, and string in function arguments for more predictable code. Second, return type declarations let you specify a function’s return type, improving readability and tool support. Third, the null coalescing operator (??) simplifies checking for null values cleanly and safely. Fourth, the spaceship operator () streamlines comparisons by returning -1, 0, or 1 based on the result. Fifth, anonymous classes enable creating one-off objects without formally defining a class. Lastly, PHP 7 brought significant performance improvements via the new Zend Engine, offering faster execution and lower memory usage.
PHP 7 brought a lot of changes that made the language faster, cleaner, and more reliable. If you're working with modern PHP or upgrading an older project, these features are definitely worth knowing.
1. Scalar Type Declarations
Before PHP 7, you could type-hint for classes, interfaces, arrays, and callables — but not for basic types like integers or strings. Now, you can enforce scalar types like int, float, bool, and string in function arguments.
For example:
function add(int $a, int $b): int {
return $a $b;
}This helps catch bugs early and makes your code more predictable. You can also enable strict typing per file using declare(strict_types=1);.
Note: Without strict mode, PHP will try to convert values if they don't match — sometimes leading to unexpected behavior.
2. Return Type Declarations
Just like scalar type hints for parameters, PHP 7 lets you define what type a function should return. This improves readability and helps tools like IDEs give better suggestions.
Example:
function getAge(): int {
return 'thirty'; // This would throw a TypeError at runtime
}Supported return types include int, string, array, bool, float, object, void, and more.
3. The Null Coalescing Operator (??)
This is a small but super useful feature. It simplifies checking for null values.
Old way:
$username = isset($_GET['user']) ? $_GET['user'] : 'guest';
New way:
$username = $_GET['user'] ?? 'guest';
It's clean, less error-prone, and avoids notices if the key doesn’t exist.
You can even chain it:
$value = $a ?? $b ?? $c ?? null;
4. Spaceship Operator (<=>)
Useful when writing custom sort functions, this operator compares two values and returns:
-1if the left side is smaller0if equal1if the right side is smaller
Example:
echo 5 <=> 10; // Outputs -1 echo 10 <=> 10; // Outputs 0 echo 15 <=> 10; // Outputs 1
This makes comparison logic much more compact and readable.
5. Anonymous Classes
If you ever needed to create one-off objects without defining a full class, PHP 7 now supports anonymous classes directly.
Example:
$logger = new class {
public function log($msg) {
echo $msg;
}
};This is especially handy for things like mock objects in testing or implementing simple interfaces on the fly.
6. Performance Improvements
One of the biggest selling points of PHP 7 was the performance boost. Thanks to the new Zend Engine (called PHPNG), PHP 7 runs significantly faster than PHP 5.6 and uses less memory.
In many real-world apps:
- Page load times dropped by 2x or more
- Memory usage cut almost in half
This means better scalability and lower server costs without changing any code.
Final thoughts
These are some of the most impactful features introduced in PHP 7. They help make code safer, cleaner, and more efficient. Once you start using them regularly, going back feels awkward — in a good way.
Most of these features are still relevant in PHP 8.x, so learning them now sets a solid foundation for future versions.
The above is the detailed content of What are some key features introduced in PHP 7 ?. For more information, please follow other related articles on the PHP Chinese website!
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