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      <center><h1>ggplot2 boxplot from continuous variable</h1></center>
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      <center><p style="max-width: 600px; margin-top: 40px">A <a href="boxplot.html">boxplot</a> summarizes the distribution of a continuous variable. This post explains how to build a boxplot with <a href="ggplot2" class="uri">ggplot2</a> where categories are actually bins of a numeric variable. It is sometimes useful to study the relationship between 2 nnumeric variables.</p></center>
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<p>Let’s say we want to study the relationship between 2 numeric variables. It is possible to cut on of them in different bins, and to use the created groups to build a <a href="boxplot.html">boxplot</a>.</p>
<p>Here, the numeric variable called <code>carat</code> from the <code>diamonds</code> dataset in cut in 0.5 length bins thanks to the <code>cut_width</code> function. Then, we just need to provide the newly created variable to the X axis of <code>ggplot2</code>.</p>
<div class="sourceCode"><pre class="sourceCode r"><code class="sourceCode r"><span class="co"># library</span>
<span class="kw">library</span>(ggplot2)
<span class="kw">library</span>(dplyr)
<span class="kw">library</span>(hrbrthemes)

<span class="co"># Start with the diamonds dataset, natively available in R:</span>
p &lt;-<span class="st"> </span>diamonds <span class="op">%&gt;%</span>
<span class="st">  </span>
<span class="st">  </span><span class="co"># Add a new column called &#39;bin&#39;: cut the initial &#39;carat&#39; in bins</span>
<span class="st">  </span><span class="kw">mutate</span>( <span class="dt">bin=</span><span class="kw">cut_width</span>(carat, <span class="dt">width=</span><span class="fl">0.5</span>, <span class="dt">boundary=</span><span class="dv">0</span>) ) <span class="op">%&gt;%</span>
<span class="st">  </span>
<span class="st">  </span><span class="co"># plot</span>
<span class="st">  </span><span class="kw">ggplot</span>( <span class="kw">aes</span>(<span class="dt">x=</span>bin, <span class="dt">y=</span>price) ) <span class="op">+</span>
<span class="st">    </span><span class="kw">geom_boxplot</span>(<span class="dt">fill=</span><span class="st">&quot;#69b3a2&quot;</span>) <span class="op">+</span>
<span class="st">    </span><span class="kw">theme_ipsum</span>() <span class="op">+</span>
<span class="st">    </span><span class="kw">xlab</span>(<span class="st">&quot;Carat&quot;</span>)</code></pre></div>
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