title: Replacing all values higher than X with NA, in only one column
body: <p>I have one column in my dataframe with extreme outliers which I would like to replace with NA. How do I go about this. Basically I would like to replace all values higher than 30 in a column with NA.</p>
  <p>I've tried these codes and none of them worked:</p>
  <pre><code>replace_with_na_all(DATAt$ColumnName, ~ .x &gt; 30)
  
  na_if(DATA, DATAt$ColumnName&gt;30)
  
  DATA[, 5][DATA[, 5] &gt;30] &lt;- NA
  </code></pre>