Sometimes special characters appear ^[[

[prem111as]

During continuous pressing of up or down Sometimes special characters appear ^ [[

[rogerdahl]

That's because the library only turns on raw mode, which hides character input, while inside the readchar() method. Any time you push a key when the program is doing something else, the terminal will echo the escape codes back. You can work around that by turning off echoing the whole time your program is running. E.g., like this example in the Python termios docs.

import termios, sys

...

if __name__ == '__main__':
    fd = sys.stdin.fileno()
    old = termios.tcgetattr(fd)
    new = termios.tcgetattr(fd)
    new[3] = new[3] & ~termios.ECHO
    try:
        termios.tcsetattr(fd, termios.TCSADRAIN, new)
        sys.exit(main())
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old)