PHP how to remove all other operators except -
<p>i want to remove all other operators except -. i worked on the following but stuck here. </p>

<pre><code>$s1 = "Hello@*&amp;^%$#@!)({}[]?.,&lt;&gt; dis$ is. testing -";
$s2 = "- i love% the way. it, works";

for($ii=0;$ii&lt;3;$ii++){

$from = array('/\(|\)/','/\d+ml|\d+g/','/\s+/'); 
$to = array('','','-'); 

$sample=${'s' . $ii}; 

$sample = strtolower(trim(preg_replace($from,$to,$sample),'-')); 
echo $sample."&lt;br&gt;";

}
</code></pre>

<p>please help me in this regards.</p>

<p><strong>Output required</strong></p>

<pre><code>hello-dis-is-testing
i-love-the-way-it-works
</code></pre>
