Please see my code below. 

this returns 
**John Doe L. R T**

I want it to return 
**John Doe L. R. T.**

```
$string = "John Doe L R T";

$matches = null;
preg_match('/\b\s[a-zA-z]{1}\b/i', $string, $matches);

foreach ($matches as $match)
{
    $string = str_replace($match, $match.'.',$string);
}

echo $string;

```