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<h1 class="title toc-ignore">Column-wise operations</h1>



<p>It’s often useful to perform the same operation on multiple columns,
but copying and pasting is both tedious and error prone:</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb1-1"><a href="#cb1-1" tabindex="-1"></