title: limit Y axis in R ggplot
body: <p>I have tried several things, but none of them worked... The thing is that I want to create a bar graph in R. The Y axis starts in 0 but I want it starts in, let's say, 300. I have tried with ylim(300,1200), but the bars dissapear. How can I do this? thanks a lot!</p>
  
  <pre><code>size &lt;- c(rep("peque", 2), rep("grande", 2))
  rt &lt;- c(900,910, 1000,1200)
  data&lt;- data.frame(size,rt)
  barra&lt;-ggplot(data, aes(size,rt))
  barra + stat_summary(fun.y= mean, geom="bar")
  </code></pre>