https://dplyr.tidyverse.org/reference/mutate.html">mutate</a></span>(<span class="kw">weeks</span><span class="kw">=</span><span class="fu"><a href="http://lubridate.tidyverse.org/reference/round_date.html">round_date</a></span>(<span class="no">date</span>, <span class="st">"weeks"</span>)) <span class="kw">%&gt;%</span> <span class="co">#we are going to take only the first date of each week</span>
  <span class="fu"><a href="https://dplyr.tidyverse.org/reference/group_by.html">group_by</a></span>(<span cl