How to read a single character from the user?

Question

Is there a way of reading one single character from the user input? For instance, they press one key at the terminal and it is returned (sort of like getch()).

Answer 1

A comment in one of the other answers mentioned cbreak mode, which is important for Unix implementations because you generally don't want ^C (KeyboardError) to be consumed by getchar (as it will when you set the terminal to raw mode, as done by most other answers).

Another important detail is that if you're looking to read one character and not one byte, you should read 4 bytes from the input stream, as that's the maximum number of bytes a single character will consist of in UTF-8 (Python 3+). Reading only a single byte will produce unexpected results for multi-byte characters such as keypad arrows.

Here's my changed implementation for Unix:

import contextlib
import os
import sys
import termios
import tty


_MAX_CHARACTER_BYTE_LENGTH = 4


@contextlib.contextmanager
def _tty_reset(file_descriptor):
    """
    A context manager that saves the tty flags of a file descriptor upon
    entering and restores them upon exiting.
    """
    old_settings = termios.tcgetattr(file_descriptor)
    try:
        yield
    finally:
        termios.tcsetattr(file_descriptor, termios.TCSADRAIN, old_settings)


def get_character(file=sys.stdin):
    """
    Read a single character from the given input stream (defaults to sys.stdin).
    """
    file_descriptor = file.fileno()
    with _tty_reset(file_descriptor):
        tty.setcbreak(file_descriptor)
        return os.read(file_descriptor, _MAX_CHARACTER_BYTE_LENGTH)