calculate array values by key : <p>i have a array  problem can i calculate same integer value.
my example arrays on the bottom please  </p>

<pre><code>int = -21;
</code></pre>

<hr>

<p>my first array</p>

<blockquote>
<pre><code>Array
(
    [580] =&gt; 13.000000
    [582] =&gt; 8.000000
    [485] =&gt; 7.000000
)
</code></pre>
</blockquote>

<p>and i need is algoritm</p>

<pre><code>Array
(
    [580] =&gt; 13.000000+int // sum -8
    [582] =&gt; 8.000000+(-8) // 0 
    [485] =&gt; 7.000000
)
</code></pre>

<p>after result</p>

<pre><code>Array
(
    [580] =&gt; 8
    [582] =&gt; 0
    [485] =&gt; 7.000000
)
</code></pre>
