How to handle parameters when creating custom PHP functions?

This article explores PHP function parameter processing techniques. Type qualification: Use type hints to enforce parameter types. Default parameter values: Set default values ​​for optional parameters. Force parameter passing: Use null union types to force parameter passing. Variable number of arguments: Use the ... syntax to receive a variable number of arguments. Through practical cases, it demonstrates how to create flexible and controllable PHP functions to handle different parameter types and requirements.

Master the skills of PHP function parameter processing and easily create flexible and controllable functions

When creating custom functions in PHP, parameter processing is crucial. It determines how the function receives input, validates input, and returns output. This article will delve into how to handle parameters in PHP functions and demonstrate its application through practical cases.

Pass parameter type qualification

For functions that require strict parameter types, you can use type hints. For example:

function sum(int $num1, int $num2): int {
    return $num1 + $num2;
}

The above function only accepts integer parameters. If other types of parameters are passed, TypeError will be raised.

Use default parameter values

When the function does not require all parameters to be specified, you can use default parameter values. For example:

function generateMessage(string $name, string $prefix = "Dear"): string {
    return "$prefix $name";
}

When calling the function, you can omit the $prefix parameter, and it will automatically use the default value "Dear".

Mandatory parameter passing

In some cases, certain parameters are essential. You can use the null union type to force parameters to be passed. For example:

function saveUser(string $username, string $email = null): void {
    // 保存用户逻辑
}

The above function requires $username as a required parameter, while $email is optional.

Handling a variable number of parameters

You can use the ... syntax to receive a variable number of parameters. For example:

function addNumbers(...$numbers): int {
    return array_sum($numbers);
}

The above function can receive any number of numbers and calculate their sum.

Practical Case

Scenario: Create a function to calculate the total salary based on given parameters.

function calculateSalary(int $baseSalary, float $bonus = 0, float $commission = 0): float {
    $totalSalary = $baseSalary;
    if ($bonus > 0) {
        $totalSalary += $bonus;
    }
    if ($commission > 0) {
        $totalSalary += $commission;
    }
    
    return $totalSalary;
}

// 例子
$baseSalary = 50000;
$bonus = 5000;
$commission = 2000;
$totalSalary = calculateSalary($baseSalary, $bonus, $commission);

echo "总薪水：$totalSalary";

This function takes $baseSalary as a required parameter and provides optional $bonus and $commission parameters. It uses type hints to enforce parameter types and calculates the total salary based on the parameter values.

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