How to update dictionary value in Swift
<p>How to 
<em>get</em> and
<em>update</em>
the  specific element from the array in the dictionary? </p>

<pre><code>var currency : [String: [Double]]  = [
    "EUR": [1,1],
    "USD": [1.06,1.05],
    "CHF": [1.07, 1.06]
]
</code></pre>

<p>I'm working on currency converter and I need to get eg. the second value (buy rate, in this case: "1.05") to make calculations. </p>