如何在Python中有效检查和更改龟坐标？

Question

I am quite new to Python and I have started a Sokoban game. I have been testing this code for checking coords to ensure the box/player moves back when walking into a wall. I tried making a little loop and the function, but I keep getting errors.

import turtle
wn=turtle.Screen()
a=turtle.Turtle()
b=turtle.Turtle()


def checking(x,y):
    if x.xcor()==y.xcor() and x.ycor()==y.ycor():
        return True
    else:
        return False


if checking(a,b)==True:
    a.xcor()=a.xcor()+50

Syntax error- Cannot assign to function call The a in the last line is highlighted.

The checking function works as this code worked perfectly.

import turtle
wn=turtle.Screen()
a=turtle.Turtle()
b=turtle.Turtle()


def checking(x,y):
    if x.xcor()==y.xcor() and x.ycor()==y.ycor():
        return True
    else:
        return False


if checking(a,b)==True:
    wn.bgcolor("blue")

I would appreciate if anyone knew a way to fix the code. Thank you!

Answer 1

This line is a problem:

a.xcor()=a.xcor()+50

as xcor() is used to access a coordinate, not set one. You want setx() :

from turtle import Screen, Turtle

wn = Screen()

a = Turtle()
b = Turtle()

def checking(x, y):
    return x.xcor() == y.xcor() and x.ycor() == y.ycor()
    # or better yet: return x.position() == y.position()

if checking(a, b):
    a.setx(a.xcor() + 50)

Here's your next issue -- the checking() function won't work in the long term. Turtles crawl a floating point plane and they often don't return to the exact position they left, eg (0, 0) vs (0, 0.001) . To deal with this, we'll need a less exact comparison:

def checking(a, b):
    return abs(a.xcor() - b.xcor()) < 1 > abs(a.ycor() - b.ycor())

or better yet:

def checking(a, b):
    return a.distance(b) < 1