title: Removing some tick labels in boxplots in ggplot2
body: <p>I'm relatively new to ggplot, so I apologize if this is easy, but I couldn't find anything online.</p>
  
  <p>I want to display 29 boxplots (numbered 1.1 to 4.0) next to each other in ggplot2 (which I can do) but once I make the tick label the appropriate size (which I can do), the labels overlap and I only want a few (1.5, 2, 2.5 etc) anyways. How can I remove only some of the tick labels? Also, anyway I can include a blank tick mark at 1.0 so my tick labels are nice, round numbers?</p>
  
  <p>My data is list which I 'melted' since each boxplot has a different number of observations.</p>
  
  <p>My current code:</p>
  
  <pre><code>list = list(data11, data12, ... data39, data40) # Elipse denotes the rest of the sequence
  df = melt(list)
  
  ggplot(df, aes(factor(variable), value)) + 
      geom_boxplot(outlier.size=1.5, colour="black") + 
      xlab("Xlabel") +
      ylab("Ylabel") +
      theme_classic() + 
      theme(
          axis.text.x = element_text(size=12),
          axis.text.y = element_text(size=12),
          axis.title.x = element_text(size=14),
          axis.title.y = element_text(size=14, angle=90),
          axis.line = element_line(size=0.75)
      )
  </code></pre>