PHP Named Arguments

Named arguments make calls with many optional parameters more readable.

What It Does

Named arguments make calls with many optional parameters more readable. The following examples distinguish a normal use case, a boundary case and a practical application.

Requirements and Compatibility

PHP 8.x and a local test environment. Apply input validation, correct error handling and the requirements of any optional libraries.

The code focuses on the core concept. Production implementation may also need routes, validation, persistence, authorization or deployment tooling.

Example 1: Basic Behavior

Start with the smallest meaningful working case.

<?php
function price(int $cents, float $tax = 0.10): float { return $cents / 100 * (1 + $tax); }
echo price(tax: 0.08, cents: 850);

Example 2: Another Case

Examine the edge case and the observable result.

<?php
function tag(string $value, string $prefix = '#', string $suffix = ''): string { return $prefix . $value . $suffix; }
echo tag('php', suffix: '!');

Practical Example: Putting It to Use

Apply the technique to a small practical task.

<?php
function crop(int $width, int $height, int $left = 0, int $top = 0): array { return compact('width', 'height', 'left', 'top'); }
print_r(crop(640, 480, top: 30));

Important Behavior and Edge Cases

Parameter names in public APIs become compatibility commitments.

Comparison with Related Functions or Approaches

Common Beginner Mistakes

Key Takeaways

• Named arguments make calls with many optional parameters more readable.
• Parameter names in public APIs become compatibility commitments.
• Positional calls remain useful for short stable signatures.

Before adapting these examples, verify the return values, test the failure paths and confirm that your application meets its security and environment requirements.