n_distinct

This is a faster and more concise equivalent of <code>length(unique(x))</code>

A fast, consistent tool for working with data frame
like objects, both in memory and out of memory.

Hadley Wickham

<dl><dt>...</dt>
<dd>vectors of values</dd>
<dt>na.rm</dt>
<dd>if <code>TRUE</code> missing values don't count</dd></dl>

<dl>

<dt>...</dt>
<dd>vectors of values</dd>


<dt>na.rm</dt>
<dd>if <code>TRUE</code> missing values don't count</dd>

</dl>