PHP format() function with named placeholders

format.php

<?php
/**
 * Return a formatted string like vsprintf() with named placeholders.
 *
 * When a placeholder doesn't have a matching key in `$args`,
 *   the placeholder is returned as is to see missing args.
 * @param string $string
 * @param array $kwargs
 * @param string $pattern
 * @return string
 */
function format($string, array $kwargs, $pattern='/\{\{(\w+)\}\}/') {
    return preg_replace_callback($pattern, function ($matches) use ($kwargs) {
        return @$kwargs[$matches[1]] ?: $matches[0];
    }, $string);
}

formatTest.php

<?php
echo format("Coordinates: {{latitude}}, {{longitude}}", ['latitude'=>'37.24N', 'longitude'=>'-115.81W']);
// => Coordinates: 37.24N, -115.81W

echo format("Coordinates: %{latitude}, %{longitude}", ['latitude'=>'37.24N', 'longitude'=>'-115.81W'], "/\%\{(\w+)\}/");
// => Coordinates: 37.24N, -115.81W

echo format("Coordinates: :latitude, :longitude", ['latitude'=>'37.24N', 'longitude'=>'-115.81W'], "/:(\w+)/");
// => Coordinates: 37.24N, -115.81W

echo format("Coordinates: {latitude}, {longitude}", ['latitude'=>'37.24N', 'longitude'=>'-115.81W'], "/\{(\w+)\}/");
// => Coordinates: 37.24N, -115.81W

echo format("Coordinates: {{latitude}}, {{longitude}}, {{timezone}}", ['latitude'=>'37.24N', 'longitude'=>'-115.81W']);
// => Coordinates: 37.24N, -115.81W, {{timezone}}