How do you put error text in a loop?

Question

My program is somewhat like this:

while True:
print("^^^options^^^")
print()
print("select your number")
print("bin [1]")
print("ban [2]")
print("bun [3]")
user_input = input("==> ")

(#the rest is output of 1 , 2, and 3)

if i were put a number other than 1, 2 , 3, you guys know that the script will loop to the 1st line.
Is there any way to put an error text like" You enter a wrong number. Please check your input" before it back to the 1st line?
Thank you. Sorry for asking a noob question!!!

Answer 1

raise(#your error): Only works for existing errors in Python
OR
if #condition:
#your error
#your code: You can create your own error

Also we were beginners once too

Answer 2

how about after the last line you add

if (user_input > 3):
print("error! wrong number! try again.")

Answer 3

lst = ['1', '2', '3']

if (user_input not in lst):
// error

Answer 4

Ypu can use raise everywhere

Answer 5

@Ali Emir Kizir:
i still confused.
Where should i put this 'raise' thing btw?
Tried once and don't get what it mean :p
Can you please write down a simple script that contain 'raise'?

Answer 6

@Mario Laurisch
JUST TRIED IT ON QPYTHON 3 AND IT WORK LIKE MAGIC!!!
THANK YOU VERY MUCH
Now I can continue my project!

Case closed

Answer 7

@Mario Laurisch
Hm, i think it was true for integer type input.
However, what if the user somewhat type a string? Thanks BTW, I can see some light :p