[Tutor] Please critique my temperature_conversion.py

[Dick Moores]

Wow, is this a great list or what?

Thanks again, tutors. By golly, I think I've got it! I decided to use 
Andrei's basic framework, and added some cool features suggested by others.

Thank you all for your kindness and patience.

Or if there's still room for improvement, please keep sending those cards 
and letters!

(I have yet to dig into sys.argv yet. Soon)

BTW I'm using Windows, so it seems I can't use/don't have the readline 
module.  BTW2 Ctrl+Break doesn't do anything, on my computer.

Dick

#TempConverter.py

"""
temperature conversion: Fahrenheit <---> Celsius. User enters temperature
    as a value (number) followed by a unit of either F or C.
    The program uses the variable "temp_value"
    to hold this original temperature value, and the variable "temp_unit"
    to hold the original F or the C.
"""

print """
       TempConverter.py

       TempConverter will convert Fahrenheit to Celsius or Celsius to 
Fahrenheit.
       Enter a temperature as a value followed by a unit (F or C),
         such as 70F, 70 f, -12.47C, 34c, etc.
       To exit program, enter exit, quit, stop, q, or x
       """

import sys, time

def exit():
     print "Thank you for using TempConverter. TempConverter will now close"
     time.sleep(1.1) # to provide the user with enough time to read the 
message

while True:
     temperature = ""

     # for exiting via ^C or ^D
     try:
         temperature = raw_input('Temperature: ').strip()
     except (TypeError, EOFError):
         break

     if temperature.lower() in ["exit", "quit", "stop", "q", "x"]:
         break

     # make sure there is input at all, i.e., catch ""; ("   " already 
stripped)
     try:
         temp_unit = temperature[-1]
         temp_value = temperature[:-1]
     except: # input is too short
         print "Wrong input! Specify a value followed by a unit."
         continue

     # make sure we know the unit
     if not (temp_unit in ['F', 'C']):
         print "Unknown unit (%s)." % temp_unit
         continue

     # make sure the value is a number
     try:
         temp_value = float(temp_value)
     except:
         print "The value you specified (%s) is not a number!" % temp_value
         continue
     #calculate new value now that sure have good value and unit
     if temp_unit == "F":
         new_value = 5/9. * (temp_value - 32)
         print "%.2fF is %.2fC" % (temp_value, new_value)
     else:
         new_value = 9/5. * temp_value + 32
         print "%.2fC is %.2fF" % (temp_value, new_value)

exit()