How to get the first key of many duplicated json key? : <p>for example `</p>

<pre><code>    $json =
    Array
    (
    [1] =&gt; b
    [1] =&gt; c
    [1] =&gt; d
    ) 
</code></pre>

<p>i just want to take the first one [1] => b and ignore the rest</p>
