ss="page-header">
    <h1>tally/count standard interface.</h1>
    <small class="dont-index">Source: <a href='https://github.com/WinVector/seplyr/blob/master/R/tally.R'><code>R/tally.R</code></a></small>
    <div class="hidden name"><code>count_se.Rd</code></div>
    </div>

    <div class="ref-description">
    <p>Add a new column named "n" with (optionally per-group) sums/counts.</p>
    </div>

    <pre class="usage"><span class='fu'>count_se</span><span class='op'>(</span><span class='va'>x</span>, grou