title: how to find out the 50% 75% and 90% point in cumulative distribution function in R
body: <p>I have a huge amount of data and I used <code>ecdf</code> function in R to calculate the cumulative distribution function. However, I can't figure out how can I get the 50% or 75% point in this function.</p>
  
  <p>For example,</p>
  
  <p>0.5 = Fn(x)</p>
  
  <p>How can I find the x value or is there any way to print out the function directly in R rather than draw the graph. </p>