Question

I have a python script that takes information from the user through the built in input() function.

My question is why do the backspace and arrow keys not function correctly and how can I fix it so they function as intended.

A simple example of the problem I am having…

#!/usr/bin/env python3
while 1:
  x=input("enter integer: ")
  y=int(x)*17
  print(y)

Here is an example of using it.

./tester 
enter integer: 3
51
enter integer: 17
289
enter integer: 172^[[D^[[D^H
Traceback (most recent call last):
  File "./tester", line 4, in <module>
    y=int(x)*17
ValueError: invalid literal for int() with base 10: '172\x08'

In trying to remove the ‘1’ using the arrow keys and backspace, ^[[D^[[D^H came up instead of deleting moving left two spaces and removing the ‘1’, and the value crashed the program.

How do I fix this so all of the keys function as intended?

Answer 1

Import the readline module from the standard library.
It automatically wraps stdin.

For example:

import readline

while True:
    response = input("> ").strip()

    if response.lower() == "quit":
        break

    print(f"You entered '{response}'")