How to re-ask for user input if user inputted a non-integer in python

while True:
    try:
        n = int(input('input your number : '))
        break
    except ValueError:
        print('You entered a non integer value, try again.')
        continue

print('yay!! you gave the correct value as int')

Now you can do any cosmetic changes as you please.

Happy coding.

Your num = int(raw_input()) has already ensured it must be an int and would raise ValueError if not int. So your while loop never gets to execute because it'll never get a non-int variable for num. Instead remove int() from the num variable and your good to go!

You can use isinstance to check whether the input is intor not.

if input is not int loop until the user enters int.

For instance:

num = input("Enter an integer:")
if not isinstance(num, int):
    while not isinstance(num, int):
        try:
            num = int(input('You must enter integer only'))
        except ValueError as ve:
            pass

Out:

Enter an integer:e
You must enter integer onlyr
You must enter integer onlye
You must enter integer only4

Process finished with exit code 0

You cast the input from the user directly to int on line 2. If this is not an integer a ValueError exception is thrown. We can modify your implementation and catch the exception when this happens, only exiting the loop when no exception occurs and num is an integer.

while True:
    num=raw_input()
    try:
        num=int(num)
        break
    except ValueError:
        print "Input is not an integer!"
print num

You might also be able to use a regular expression to check if the input value is an integer, or some other library function that checks whether the string from raw_input() is an integer.