title: Cost of exception handlers in Python
body: <p>In <a href="https://stackoverflow.com/questions/2521558/avoid-if-statement-after-condition-has-been-met">another question</a>, the accepted answer suggested replacing a (very cheap) if statement in Python code with a try/except block to improve performance.</p>
  
  <p>Coding style issues aside, and assuming that the exception is never triggered, how much difference does it make (performance-wise) to have an exception handler, versus not having one, versus having a compare-to-zero if-statement?</p>