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<title>multiple-return-values</title>
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<p>#Multiple Return Types</p>
<p>To return multiple things use <code>values</code>!</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode commonlisp"><code class="sourceCode commonlisp"><a class="sourceLine" id="cb1-1" title="1">(<span class="kw">defun</span><span class="fu"> average </span>(&<span class="kw">rest</span> nums)</a>
<a class="sourceLine" id="cb1-2" title="2"> (<span class="kw">let</span> ((mean(<span class="op">/</span> (<span class="kw">apply</span> #'+ nums) (<span class="kw">length</span> nums)))</a>
<a class="sourceLine" id="cb1-3" title="3"> (median (<span class="kw">nth</span> (<span class="kw">floor</span> (<span class="op">/</span> (<span class="kw">length</span> nums) <span class="dv">2</span>)) (<span class="kw">sort</span> nums #'<))))</a>
<a class="sourceLine" id="cb1-4" title="4"> (<span class="kw">values</span> mean median)))</a>
<a class="sourceLine" id="cb1-5" title="5"><span class="co">;; => AVERAGE</span></a>
<a class="sourceLine" id="cb1-6" title="6"></a>
<a class="sourceLine" id="cb1-7" title="7">(average <span class="fl">1.1</span> <span class="dv">2</span> <span class="dv">3</span> <span class="dv">54</span> <span class="dv">5</span> <span class="dv">7</span> <span class="dv">7</span> <span class="dv">8</span>)</a>
<a class="sourceLine" id="cb1-8" title="8"><span class="co">;; => 10.8875</span></a>
<a class="sourceLine" id="cb1-9" title="9"><span class="co">;; 7</span></a></code></pre></div>
<p>return multiple values as a list</p>
<div class="sourceCode" id="cb2"><pre class="sourceCode commonlisp"><code class="sourceCode commonlisp"><a class="sourceLine" id="cb2-1" title="1">(<span class="kw">multiple-value-list</span> (<span class="kw">values</span> <span class="dv">1</span> <span class="dv">2</span> <span class="dv">4</span>))</a>
<a class="sourceLine" id="cb2-2" title="2"><span class="co">;; => (1 2 4)</span></a></code></pre></div>
<div class="sourceCode" id="cb3"><pre class="sourceCode commonlisp"><code class="sourceCode commonlisp"><a class="sourceLine" id="cb3-1" title="1">(<span class="kw">multiple-value-bind</span> (a b c) (<span class="kw">values</span> <span class="dv">1</span> <span class="dv">2</span> <span class="dv">3</span>)</a>
<a class="sourceLine" id="cb3-2" title="2"> (<span class="kw">format</span> <span class="kw">nil</span> <span class="st">"(a b c) - easy as ~a ~a ~a"</span> a b c))</a>
<a class="sourceLine" id="cb3-3" title="3"> </a>
<a class="sourceLine" id="cb3-4" title="4"><span class="co">;; => "(a b c) - easy as 1 2 3"</span></a></code></pre></div>
<ul>
<li><code>multiple-value-bind</code> creates a lexical scope where the multiple values returned by a form are bound to variables you supply - kinda like <code>let</code>.</li>
</ul>
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