PHP string formatting function

examples.php

<?php

include 'str_format.php';

// example 1
echo str_format(':foo + :bar = :baz', array(
	'foo' => 5,
	'bar' => 6,
	'baz' => 11,
));

// example 2
// repeated keys
echo str_format(':foo + :foo = :bar', array(
	'foo' => 3,
	'bar' => 6,
));

// example 3
// numbered keys
echo str_format(':0 + :1 = :2', array(
	5,
	6,
	11,
));

// example 4
// custom prefix
echo str_format('%foo + %bar = %baz', array(
	'foo' => 5,
	'bar' => 6,
	'baz' => 11,
), '%');

str_format.php

<?php

function str_format($subject, $replacements, $prefix = ':')
{
	foreach($replacements as $key => $value)
	{
		$subject = str_replace($prefix.$key, $value, $subject);
	}
	
	return $subject;
}