How to set type hints for PHP function parameters?

How to perform PHP parameter type hinting? 1. Use a colon after the parameter name to specify the type; 2. PHP provides built-in types such as int, float, string, etc.; 3. Using type hints can improve code readability, improve performance, and enable IDE functions; 4. Ensure that the function only receives the correct type to prevent unexpected errors.

#How to set type hints in PHP function parameters?

Type hints are a feature in PHP that allow you to specify the data type of function parameters. This provides the following benefits:

• Improved code readability and maintainability: When you see a function signature with type hints, you will immediately know that the function requires What kind of input.
• Improve performance: PHP automatically enforces type hints at runtime. This helps identify and prevent type mismatch errors.
• Enable IDE features: Many IDEs use type hints to provide code autocompletion, refactoring, and other features that help write correct code.

Set type hints

To set type hints for a parameter of a PHP function, follow the parameter name with a colon (:) and then specify the type. Here are some examples:

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

function greet(string $name): void
{
    echo "Hello, $name!";
}

function divide(float $a, float $b): float
{
    return $a / $b;
}

Built-in types

PHP provides the following built-in types:

• int - Integer
• float - Floating point number
• string - String
• null - Null value
• void - Indicates that the function does not return any value
• array - Array
• bool - Boolean value
• callable - Callable item
• iterable - Iterable item

Practical case

Let us consider an example where we use type hints for a function that calculates the sum of two numbers:

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

// 正确的用法
$result = sum(1, 2);

// 抛出 TypeError 异常
sum("1", "2"); // 字符串参数，需要整数

By using type hints, we ensure that sum() The function only accepts integer arguments, preventing unexpected type mismatch errors.

Note:

• Type hints are supported in PHP 7.0 and later.
• Type hints are not required, but their use is highly recommended to write more robust and reliable code.

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