>13.2.7</b> Joining tables</a></li>
<li class="chapter" data-level="13.2.8" data-path="tidyverse.html"><a href="tidyverse.html#changing-the-order-of-columns"><i class="fa fa-check"></i><b>13.2.8</b> Changing the order of columns</a></li>
<li class="chapter" data-level="13.2.9" data-path="tidyverse.html"><a href="tidyverse.html#calculations-by-group"><i class="fa fa-check"></i><b>13.2.9</b> Calculations by group</a></li>
<li class="chapter" data-level="13.2.10" data-path="tidyverse.html"><a href="tidyverse.h