allow only space, letters and 1 dot in php
<p>good day stackoverflow.</p>

<p>I have this code which allows only letters but I want to allow only spaces, letters and 1 dot.</p>

<pre><code>if(!preg_match('/[^a-zA-Z]/', $fullname)) {

}
</code></pre>

<p>thanks in advance </p>

<p>edit:
I want to allow this string</p>

<p>$fullname = "Mark E. Zuckerberg";
or 
$fullname = "Zuckerberg Mark E.";</p>