<p>Each array variable, <code>let</code> binding, or stored property has an
independent value that includes the values of all of its elements.
Therefore, mutations to the array are not observable through its
copies:</p>

<pre><code class="language-swift">var a = [1, 2, 3]
var b = a
b[0] = 4
print(&quot;a=\(a), b=\(b)&quot;)     // a=[1, 2, 3], b=[4, 2, 3]</code></pre>

<p>(Of course, if the array stores <code>class</code> references, the objects
are shared; only the values of the references are independent.