title: Is there a way to limit vline lengths in ggplot2
body: <p>I'm trying to show an intercept on a line graph using the ggplot vline and hline but want the lines to cease at the point of interception on the graph. Is this possible either in ggplot or is there another solution</p>
  
  <pre><code>library(ggplot2)
  
  pshare &lt;- data.frame()
  
  for (i in 1:365) {
    pshare &lt;- rbind(pshare,c(i, pbirthday(i,365,coincident=3)))
  }
  
  names(pshare) &lt;- c("number","probability")
  
  x25 &lt;- qbirthday(prob = 0.25, classes = 365, coincident = 3) #61
  x50 &lt;- qbirthday(prob = 0.50, classes = 365, coincident = 3)
  x75 &lt;- qbirthday(prob = 0.75, classes = 365, coincident = 3)
  
  p &lt;- qplot(number,probability,data=subset(pshare,probability&lt;0.99))
  
  p &lt;- p + geom_vline(xintercept = c(x25,x50,x75))
  p &lt;- p + geom_hline(yintercept = c(0.25,0.5,0.75))
  p
  </code></pre>
  
  <p>So, for example, I would like the 0.25/61 lines to end when they meet on the plot</p>
  
  <p>TIA</p>