 class="external-link">data</a></span><span class="op">(</span><span class="va">ipdna_md</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="co">## maybe str(ipdna_md)</span></span></span>
<span class="r-in"><span></span></span>
<span class="r-in"><span><span class="co">#summary per study</span></span></span>
<span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/base/by.html" class="external-link">by</a></span><span class="op">(</span><span class="va">ipdna