I like decorators to separate the checking from the rest of the input handling.

#!/usr/bin/env python def repeatOnError(function): def checked(*args, **kwargs): while True: try: result = function(*args, **kwargs) except Exception as problem: print "There was a problem with the input:" print problem print "Please repeat!"    else: return result return checked @repeatOnError def getNumberOfIterations(): return int(raw_input("Please enter the number of iterations: ")) iterationCounter = getNumberOfIterations() print "You have chosen", iterationCounter, "iterations." 

I like decorators to separate the checking from the rest of the input handling.

#!/usr/bin/env python def repeatOnError(*exceptions): def checking(function):   def checked(*args, **kwargs):   while True:   try:   result = function(*args, **kwargs)   except exceptions as problem:   print "There was a problem with the input:"   print problem.__class__.__name__   print problem  print "Please repeat!"   else:    return result   return checked  return checking  @repeatOnError(ValueError) def getNumberOfIterations(): return int(raw_input("Please enter the number of iterations: ")) iterationCounter = getNumberOfIterations() print "You have chosen", iterationCounter, "iterations." 

EDIT:

A decorator is more or less a wrapper for an existing function (or method). It takes the existing function (denoted below its @decorator directive) and returns a "replacement" for it. This replacement in our case calls the original function in a loop and catches any exception happening while doing so. If no exception happens, it just returns the result of the original function.