In your terminal (or anacoonda prompt) run this command to install pynput library:

pip install pynput

And, in your editor

from pynput import keyboard
from pynput.keyboard import Key

def on_key_release(key):
    if key == Key.right:
        print("Right key clicked")
    elif key == Key.left:
        print("Left key clicked")
    elif key == Key.up:
        print("Up key clicked")
    elif key == Key.down:
        print("Down key clicked")
    elif key == Key.esc:
        exit()


with keyboard.Listener(on_release=on_key_release) as listener:
    listener.join()

More info

I think I figured it out.

I learned from here that each arrow key is represented by a unique ANSI escape code. Then I learned that the ANSI escape codes vary by system and application: in my terminal, hitting cat and pressing the up-arrow gives ^[[A, in C it seems to be \033[A, etc. The latter part, the [A, remains the same, but the code for the preceding Escape can be in hex(beginning with an x), octal (beginning with a 0), or decimal(no lead in number).

Then I opened the python console, and plugged in the triples I had previously received, trying to find their character values. As it turned out, chr(27) gave \x1b, chr(91) gave [, and calling chr on 65,66,67,68 returned A,B,C,D respectively. Then it was clear: \x1b was the escape-code!

Then I noted that an arrow key, in ANSI represented as a triple, is of course represented as three characters, so I needed to amend my code so as to read in three characters at a time. Here is the result:

import sys,tty,termios
class _Getch:
    def __call__(self):
            fd = sys.stdin.fileno()
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(sys.stdin.fileno())
                ch = sys.stdin.read(3)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
            return ch

def get():
        inkey = _Getch()
        while(1):
                k=inkey()
                if k!='':break
        if k=='\x1b[A':
                print "up"
        elif k=='\x1b[B':
                print "down"
        elif k=='\x1b[C':
                print "right"
        elif k=='\x1b[D':
                print "left"
        else:
                print "not an arrow key!"

def main():
        for i in range(0,20):
                get()

if __name__=='__main__':
        main()

curses is exactly what you want. In fact I believe vim implements its interface with curses.

Try to put the following code into a file called test_curses.py:

import curses

screen = curses.initscr()
screen.addstr("Hello World!!!")
screen.refresh()
screen.getch()
curses.endwin()

Now open a terminal (not IDLE! a real terminal!) and run it via:

python test_curses.py

You should see that the terminal was cleared and an Hello World!!! writing appeared. Press any key and the program will stop, restoring the old terminal contents.

Note that the curses library isn't as easy and "user-friendly" as you may be accustomed to. I suggest reading the tutorial (unfortunately for the C language, but the python interface is mostly the same)

System sends to programs information about pressed key ("events") only when key changes state from not-pressed to pressed or from pressed to not-pressed (released). It doesn't send events when you hold down key.

You have to use onkeypressed() to set arrow_up_pressed = True and onkeyreleased() to reset arrow_up_pressed = False and ontimer() to run repeatedly code which checks if arrow_up_pressed is True and move object up. The same you should do with arrow_down_pressed, etc.

Or you can use variable speed instead of arrow_up_pressed and arrow_down_pressed so you can assing +15 or -15 to the same variable (or 0 when keys are released). And again you need ontimer to run repeatedly code which add speed to position.

In example I use second method.

Minimal working code

import turtle

def paddle_a_up():
    global a_speed_y

    a_speed_y = +15

def paddle_a_down():
    global a_speed_y
    
    a_speed_y = -15

def paddle_a_left():
    global a_speed_x

    a_speed_x = -15

def paddle_a_right():
    global a_speed_x
    
    a_speed_x = +15

def paddle_a_stop_y():
    global a_speed_y

    a_speed_y = 0

def paddle_a_stop_x():
    global a_speed_x

    a_speed_x = 0

def update_frame():
    x, y = paddle_a.position()
    
    y += a_speed_y
    x += a_speed_x

    paddle_a.goto(x, y)

    # here update position for other objects - ie. move ball

    # run again after 50ms
    wn.ontimer(update_frame, 50)  # 50ms means ~20 FPS (Frames Per Second) (1000/50 = 20)

# --- main ---

# default values at start
a_speed_x = 0
a_speed_y = 0

wn = turtle.Screen()
paddle_a = turtle.Turtle()

# run first time after 50ms
wn.ontimer(update_frame, 50)  # 50ms means ~20 FPS (Frames Per Second) (1000ms / 50ms = 20)

# binds
wn.onkeypress(paddle_a_up, "Up")
wn.onkeypress(paddle_a_down, "Down")
wn.onkeypress(paddle_a_left, "Left")
wn.onkeypress(paddle_a_right, "Right")

wn.onkeyrelease(paddle_a_stop_y, "Up")
wn.onkeyrelease(paddle_a_stop_y, "Down")
wn.onkeyrelease(paddle_a_stop_x, "Left")
wn.onkeyrelease(paddle_a_stop_x, "Right")

wn.listen()
wn.mainloop()

BTW: The same way you would have to do this in PyGame or Pyglet.

You get better result if you add/substract value to speed instead of assigning - because when you press left and right at the same time then it will stop move (because speed +15 and -15 will gives 0), and when you release only one - ie. left - then it will again move right. In previous version when you release one but you still keep pressed other then it doesn't move again.

import turtle

def paddle_a_up_pressed():
    global a_speed_y

    a_speed_y += 15

def paddle_a_down_pressed():
    global a_speed_y
    
    a_speed_y -= 15

def paddle_a_left_pressed():
    global a_speed_x

    a_speed_x -= 15

def paddle_a_right_pressed():
    global a_speed_x
    
    a_speed_x += 15

def paddle_a_up_released():
    global a_speed_y

    a_speed_y -= 15

def paddle_a_down_released():
    global a_speed_y

    a_speed_y += 15

def paddle_a_left_released():
    global a_speed_x

    a_speed_x += 15

def paddle_a_right_released():
    global a_speed_x

    a_speed_x -= 15


def update_frame():
    x, y = paddle_a.position()
    
    x += a_speed_x
    y += a_speed_y

    paddle_a.goto(x, y)

    # run again after 50ms
    wn.ontimer(update_frame, 50)  # 50ms means ~20 FPS (Frames Per Second) (1000/50 = 20)

# --- main ---

# default values at start
a_speed_x = 0
a_speed_y = 0

wn = turtle.Screen()
paddle_a = turtle.Turtle()

# run first time after 50ms
wn.ontimer(update_frame, 50)  # 50ms means ~20 FPS (Frames Per Second) (1000/50 = 20)

# binds
wn.onkeypress(paddle_a_up_pressed, "Up")
wn.onkeypress(paddle_a_down_pressed, "Down")
wn.onkeypress(paddle_a_left_pressed, "Left")
wn.onkeypress(paddle_a_right_pressed, "Right")

wn.onkeyrelease(paddle_a_up_released, "Up")
wn.onkeyrelease(paddle_a_down_released, "Down")
wn.onkeyrelease(paddle_a_left_released, "Left")
wn.onkeyrelease(paddle_a_right_released, "Right")

wn.listen()
wn.mainloop()

It's the same with pyautogui, and keyboard. Just use the word for direction. For example, 'right', or 'left'. Like this:

import keyboard

keyboard.press_and_release('left') #presses left arrow key

I recommend looking at the documentation to find key codes, as to find the difference between arrows on the numpad and normal layout can be difficult, and just for general reference in the future.

probably worth looking into the curses library for this

There are different situations:

• If you use a graphical frontend such as TKinter or PyGame, you can bind an event to the arrow key and wait for this event.

  Example in Tkinter taken from this answer:

  from Tkinter import *
  
  main = Tk()
  
  def leftKey(event):
      print "Left key pressed"
  
  def rightKey(event):
      print "Right key pressed"
  
  frame = Frame(main, width=100, height=100)
  main.bind('<Left>', leftKey)
  main.bind('<Right>', rightKey)
  frame.pack()
  main.mainloop()
  

• If your application stays in the terminal, consider using curses as described in this answer

  Curses is designed for creating interfaces that run in terminal (under linux).

• If you use curses, the content of the terminal will be cleared when you enter the application, and restored when you exit it. If you don't want this behavior, you can use a getch() wrapper, as described in this answer. Once you have initialized getch with getch = _Getch(), you can store the next input using key = getch()

As to how to call display() every second, it again depends on the situation, but if you work in a single process in a terminal, the process won't be able to call your display() function while it waits for an input. The solution is to use a different thread for the display() function, as in

import threading;

def display (): 
    threading.Timer(1., display).start ();
    print "display"

display ()

Here display schedules itself one second in the future each time it is called. You can of course put some conditions around this call so that the process stops when some conditions are met, in your case when an input has been given. Refer to this answer for a more thoughout discussion.

Using Tkinter you can do the following .... I found it on the net

# KeyLogger_tk2.py
# show a character key when pressed without using Enter key
# hide the Tkinter GUI window, only console shows

try:
   # Python2
    import Tkinter as tk
except ImportError:
    # Python3
    import tkinter as tk

def key(event):
"""shows key or tk code for the key"""
    if event.keysym == 'Escape':
        root.destroy()
    if event.char == event.keysym:
     # normal number and letter characters
        print( 'Normal Key %r' % event.char )
    elif len(event.char) == 1:
      # charcters like []/.,><#$ also Return and ctrl/key
        print( 'Punctuation Key %r (%r)' % (event.keysym, event.char) )
    else:
      # f1 to f12, shift keys, caps lock, Home, End, Delete ...
        print( 'Special Key %r' % event.keysym )


root = tk.Tk()
print( "Press a key (Escape key to exit):" )
root.bind_all('<Key>', key)
# don't show the tk window
root.withdraw()
root.mainloop()

The documentation says:

If the readline module was loaded, then input() will use it to provide elaborate line editing and history features.

In your example, you haven't loaded the readline module. Compare the behavior of this:

x = input('enter a number:')
print(x)

To this:

import readline
x = input('enter a number:')
print(x)

The second example will behave as you expect (readline support is active, arrow keys work, etc) while the first example will not have readline support.

On the command line, this would be:

python3 -c "import readline; x=input('enter a number '); print(x)"