Python attribute error onkeypress

Question

I am new to Python. I use IDLE (Using python 2.7) on my raspberry pi. I've been unable to compile the latest program from my tutorial, a cat and mouse game. I get the following error:

Traceback (most recent call last) : 
  File  "/home/pi/pyth-prog/Python_Cat_and-mouse.py", line 47, in <module> window.onkeypress(up,  "Up") 
AttributeError:  '__Screen'  object has no attribute 'onkeypress' 

My code looks like this:

import turtle
import time


boxsize =200
caught= False
score= 0


#function that are called keypresses
def up():
    mouse.forward(10)
    checkbound()


def left():
    mouse.left(45)


def right():
    mouse.right(45)


def back():
    mouse.back(10)


def quitTurtles():
    window.bye()


#stop the ;ouse fro; leaving the square set by box sizes

def checkbound():
    global boxsize
    if mouse.xcor() > boxsize:
        mouse.goto(boxsize, mouse.ycor())
    if mouse.xcor() < -boxsize:
        mouse.goto(-boxsize, mouse.ycor())
    if mouse.ycor() > boxsize:
        mouse.goto(mouse.xcor(), boxsize)
    if mouse.ycor < -boxsize:
        mouse.goto(mouse.xcor(), -boxsize)


#Set up screen
window=turtle.Screen()
mouse=turtle.Turtle()
cat=turtle.Turtle()
mouse.penup()
mouse.penup()
mouse.goto(100, 100)


#add key listeners
window.onkeypress(up, "Up")
window.onkeypress(left, "Left")
window.onkeypress(right, "Right")
window.onkeypress(back, "Down")
window.onkeypress(quitTurtles, "Escape")


difficulty=window.numinput("Difficulty", "Enter a difficulty from easy (1), for hard (5) ", minval=1, maxval=5)


window.listen()




#main loop
#note how it changes with difficulty




while not caught:
    cat.setheading(cat.towards(mouse))
    cat.forward(8+difficulty)


    score=score+1
    if cat.distance(mouse) < 5:
        caught=True
    time.sleep(0.2-(0.01*difficulty))
window.textinput("GAME OVER", "Well done. You scored:"+ str(score*difficulty))
window.bye()

Answer 1

I use IDLE(Using python 2.7) on my raspberry pi

The turtle.py for Python 2.7 only defines onkey() -- the onkeypress() variant was added in Python 3 (as was a synonym for onkey() called onkeyrelease())

Short answer, try changing onkeypress() to onkey().

Once you get past that hurdle, numinput() and textinput() are also Python 3:

difficulty=window.numinput("Difficulty", "Enter a difficulty from easy (1), for hard (5) ", minval=1, maxval=5)
...
window.textinput("GAME OVER", "Well done. You scored:"+ str(score*difficulty))

so they may need to be dealt with too.

Answer 2

Based on turtle from Python 3.5.

It doesn't neeed window. but has to be executed after turtle.Screen()

import turtle

# --- based on turtle in Python 3.5 --- 

import tkSimpleDialog

def numinput(title, prompt, default=None, minval=None, maxval=None):
    return tkSimpleDialog.askfloat(title, prompt, initialvalue=default,
                                     minvalue=minval, maxvalue=maxval)

def textinput(title, prompt):
    return tkSimpleDialog.askstring(title, prompt)

# --- main ---

window = turtle.Screen()

# doesn't need `window.` but has to be executed after `turtle.Screen()`

difficulty = numinput("Difficulty", "Enter a difficulty from easy (1), for hard (5) ", minval=1, maxval=5)

textinput("GAME OVER", "Well done. You scored:" + str(0))