validation_imgs &lt;- <span class="kw">c</span>(cans[<span class="dv">1</span><span class="op">:</span><span class="dv">5</span>], cartons[<span class="dv">1</span><span class="op">:</span><span class="dv">5</span>], milk[<span class="dv">1</span><span class="op">:</span><span class="dv">5</span>], water[<span class="dv">1</span><span class="op">:</span><span class="dv">5</span>])</span>
<span id="cb10-2"><a href="#cb10-2"></a>validation_tags &lt;- <span class="kw">rep</span>(<span class="kw">c</span>(<spa