</a></span>
<span id="cb403-8"><a href="loops.html#cb403-8" tabindex="-1"></a><span class="do">## Warning in multiply_columns(x = city[, i], y = city[, i + 1]): The function has</span></span>
<span id="cb403-9"><a href="loops.html#cb403-9" tabindex="-1"></a><span class="do">## produced NAs</span></span></code></pre></div>
<p>When we specify our <code>for</code> loop notice how we subtracted 1 from <code>ncol(city)</code>. The <code>ncol()</code> function returns the number of columns in our <code>city</code