title: Is there an option to set "," as default decimal point for axis labels in ggplot?
body: <p>When making a graph, <code>ggplot2</code> has a lot of sensible defaults for scales that require extra work when trying to achieve the same result using <code>scales</code>.</p>
  <p>An example:</p>
  <pre><code>library(&quot;ggplot2&quot;)
  ggplot(mtcars, aes(drat, mpg)) + geom_point()
  </code></pre>
  <p>Note that this plot has one digit behind the decimal mark.</p>
  <p>However, I live in the Netherlands and we're used to using a comma as decimal mark. This is easily done within <code>scale_x_continuous</code>:</p>
  <pre><code>ggplot(mtcars, aes(drat, mpg)) + 
    geom_point() + 
    scale_x_continuous(labels = scales::label_number(big.mark = &quot;.&quot;, decimal.mark = &quot;,&quot;))
  </code></pre>
  <p>What bugs me about this solution is that this also increases the number of digits: there's an extra, rather unnecessary, 0 at the end of each label. Of course, this can also be solved within <code>scales::label_number()</code>, by setting <code>accuracy = 0.1</code> but that requires iteration (plotting and re-plotting to set the more sensible number of digits).</p>
  <p>Is there an option to fix the default decimal mark used by ggplot? I'm looking for a solution where</p>
  <pre><code>ggplot(mtcars, aes(drat, mpg)) + 
    geom_point()
  </code></pre>
  <p>returns the same plot as</p>
  <pre><code>ggplot(mtcars, aes(drat, mpg)) + 
    geom_point() + 
    scale_x_continuous(labels = scales::label_number(
      big.mark = &quot;.&quot;, 
      decimal.mark = &quot;,&quot;,
      accuracy = 0.1
    ))
  </code></pre>