title: How to reverse legend (labels and color) so high value starts at bottom?
body: <p>whats the best way to invert the legend label order so the 7 is down and the 1 is upstairs?</p>
  
  <p><img src="https://i.stack.imgur.com/jRUc6.png" alt="ggplot legend challenge"></p>
  
  <pre><code>df$day &lt;- as.numeric(df3$day)
  blues &lt;- colorRampPalette(c('#132B43', '#56B1F7'))
  
  p4 &lt;- 
      ggplot(subset(df,feedback==1&amp;stp&gt;20), aes(x=correct, fill=day, colour=day)) +
      geom_histogram(colour="black", binwidth=10) +
      facet_grid(day ~ .) +
      ggtitle("Over-pronation histogram") +
      ylab("Count (150s period)") +
      xlab("% Steps in over-pronation") +guide_legend(reverse = false)
  </code></pre>