ndition)` when condition evaluates to NA. Example below\n\n``` R\nx &lt;- data.frame(v1 = c(1, 2, NA))\n#&gt;  v1\n#&gt;1  1\n#&gt;2  2\n#&gt;3 NA\nfilter(x, !(v1 == 1))\n#&gt;  v1\n#&gt;1  2\ndiscard(x, v1 == 1)\n#&gt;  v1\n#&gt;1  2\n#&gt;2 NA\n```\n</span>
<span class="co">#&gt; 5                                                                                                                                                                                                                                    