title: Reading a .csv file and doing simple statistics in ruby
body: <p>I'm generating some load test results with jmeter and it outputs nicely formatted csv file, but now I need to do some number crunching with ruby. An example beginning of the csv file:</p>
  
  <pre><code>threadName,grpThreads,allThreads,URL,Latency,SampleCount,ErrorCount
  Thread Group 1-1,1,1,urlXX,240,1,0
  Thread Group 1-1,1,1,urlYY,463,1,0
  Thread Group 1-2,1,1,urlXX,200,1,0
  Thread Group 1-3,1,1,urlXX,212,1,0
  Thread Group 1-2,1,1,urlYY,454,1,0
  .
  .
  .
  Thread Group 1-N,1,1,urlXX,210,1,0
  </code></pre>
  
  <p>Now, for statistics I need to read the first line of each thread group, add the Latency fields up and then divide with the amount of thread groups I have, to just get an average latency. Then iterate to the second line of every thread group and so forth..</p>
  
  <p>I was thinking that maybe I would need to write some temporary sorted csv files for each thread group (the order of the url's are hit is always the same within a thread group) and then use those as input, add first lines, do math, add second lines until there are no more lines.</p>
  
  <p>But since the amount of thread groups change, I haven't been able to write ruby so that it could flex around that... any code examples would be really appreciated :)</p>