In php, why array_unshift() is named unshift?
<p>As we know, there are four functions that can be used to insert into and delete from an array:</p>

<ol>
<li>array_push()</li>
<li>array_pop()</li>
<li>array_unshift()</li>
<li>array_shift()</li>
</ol>

<p>What's the meaning of <code>array_unshift()</code> and <code>array_shift()</code>, I mean why they are named like this?</p>
