Exit while loop by user hitting ENTER key

Question

I am a python newbie and have been asked to carry out some exercises using while and for loops. I have been asked to make a program loop until exit is requested by the user

Answer 1

user_input=input("ENTER SOME POSITIVE INTEGER : ")
if((not user_input) or (int(user_input)<=0)):    
   print("ENTER SOME POSITIVE INTEGER GREATER THAN ZERO") #print some info
   import sys        #import
   sys.exit(0)       #exit program 
'''
#(not user_input) checks if user has pressed enter key without entering  
# number.
#(int(user_input)<=0) checks if user has entered any number less than or 
#equal to zero.
'''

Answer 2

Actually, I suppose you are looking for a code that runs a loop until a key is pressed from the keyboard. Of course, the program shouldn't wait for the user all the time to enter it.

1. If you use raw_input() in python 2.7 or input() in python 3.0, The program waits for the user to press a key.
2. If you don't want the program to wait for the user to press a key but still want to run the code, then you got to do a little more complex thing where you need to use kbhit() function in msvcrt module.

Actually, there is a recipe in ActiveState where they addressed this issue. Please follow this link

I think the following links would also help you to understand in much better way.

1. python cross platform listening for keypresses

2. How do I get a single keypress at a time

3. Useful routines from the MS VC++ runtime

I hope this helps you to get your job done.