How to compare 2 arrays in PHP?
<p>This is the first array:</p>

<pre><code>$possible_combinations = array(
    1 =&gt; array(1),
    2 =&gt; array(2),
    3 =&gt; array(3),
    4 =&gt; array(4),

    5 =&gt; array(1, 2),
    6 =&gt; array(1, 3),
    7 =&gt; array(1, 4),       

    8 =&gt; array(2, 3),
    9 =&gt; array(2, 4),       

    10 =&gt; array(3, 4),

    11 =&gt; array(2, 3, 4),
    12 =&gt; array(1, 3, 4),
    13 =&gt; array(1, 2, 4),
    14 =&gt; array(1, 2, 3),

    15 =&gt; array(1, 2, 3, 4)
);
</code></pre>

<p>This is the second array:</p>

<pre><code>$seeking = array(2, 3, 4);
</code></pre>

<p>As you can see <code>$possible_combinations[11]</code> matches <code>$seeking</code>. </p>

<p>The value of $seeking in this case is 2, 3, 4 but it may be different at other times. How can I run a check against the
$possible_combinations array to see if the $seeking array matches any of the values of that associative array. 
It should return the key of the match if there is one.</p>
