title: Python csv.writer control precision
body: <p>i'm using the standard csv.writer like so</p>
  
  <pre><code>wr = csv.writer(f,csv.QUOTE_NONNUMERIC)
  wr.writerows(output)
  </code></pre>
  
  <p>and i would like to be able to format the csv file so that every column has %3.4e. output is a 2 dimensional list. right now, it seems to be writing it out in whatever precisions the values were stored in, which can be variable. i also don't know at code time the size of each dimension, specifically, how many elements are in each row, so i can't simply write out a big format string. is there a simple way to use the csv.writer to just write every numeric value with a certain precision?</p>