>y =</span> city[, i <span class="sc">+</span> <span class="dv">1</span>])</span>
<span id="cb403-4"><a href="loops.html#cb403-4" tabindex="-1"></a>}</span>
<span id="cb403-5"><a href="loops.html#cb403-5" tabindex="-1"></a><span class="do">## Warning in multiply_columns(x = city[, i], y = city[, i + 1]): The function has</span></span>
<span id="cb403-6"><a href="loops.html#cb403-6" tabindex="-1"></a><span class="do">## produced NAs</span></span>
<span id="cb403-7"><a href="loops.html#cb403-7" tabindex="-1">