python - 当一只正在移动的 Python turtle 靠近另一只 turtle 时，阻止它

Question

当一只随机移动的 turtle 与另一只 turtle 的 50 个单位一起出现时，如何使用 while 循环停止它？

我有一只 turtle ，它随机选择一个位置并创建一个大点或洞，另一只 turtle 随机移动，进行 90 度转弯，每次向前移动 50 个单位。随机移动的 turtle 在离开屏幕末端时会停止，但是当它到达另一只 turtle 创建的洞时，如何让 turtle 停止呢？

import random
import turtle

def turtlesClose(t1, t2):
    if t1.distance(t2)<50:
        return True
    else:
        return False

def isInScreen(win,turt):
    leftBound = -win.window_width() / 2
    rightBound = win.window_width() / 2
    topBound = win.window_height() / 2
    bottomBound = -win.window_height() / 2

    turtleX = turt.xcor()
    turtleY = turt.ycor()

    stillIn = True
    if turtleX > rightBound or turtleX < leftBound:
        stillIn = False
    if turtleY > topBound or turtleY < bottomBound:
        stillIn = False
    return stillIn

def main():
    wn = turtle.Screen()
    # Define your turtles here
    june = turtle.Turtle()
    july = turtle.Turtle()

    july.shape('turtle')
    july.up()
    july.goto(random.randrange(-250, 250, 1), random.randrange(-250, 250, 1))
    july.down()
    july.dot(100)

    june.shape('turtle')
    while isInScreen(wn,june):
        coin = random.randrange(0, 2)
        dist = turtlesClose(july, june)
        if coin == 0:
            june.left(90)
        else:
            june.right(90)
        june.forward(50)

        if dist == 'True':
            break

main()

Answer 1

您的代码的问题在于以下语句:

if dist == 'True':

您不需要在 True 周围加上引号。虽然这会起作用:

if dist == True:

正确的表达方式是:

if dist is True:

或者更好:

if dist:

否则你的代码似乎可以工作。下面是利用一些 turtle 习语和其他代码清理的重写:

from random import randrange, choice
from turtle import Screen, Turtle

CURSOR_SIZE = 20

def turtlesClose(t1, t2):
    return t1.distance(t2) < 50

def isInScreen(window, turtle):
    leftBound = -window.window_width() / 2
    rightBound = window.window_width() / 2
    topBound = window.window_height() / 2
    bottomBound = -window.window_height() / 2

    turtleX, turtleY = turtle.position()

    return leftBound < turtleX < rightBound and bottomBound < turtleY < topBound

def main():
    screen = Screen()

    july = Turtle('circle')
    july.shapesize(100 / CURSOR_SIZE)

    july.up()
    july.goto(randrange(-250, 250), randrange(-250, 250))
    july.down()

    june = Turtle('turtle')

    while isInScreen(screen, june):

        if turtlesClose(july, june):
            break

        turn = choice([june.left, june.right])

        turn(90)

        june.forward(50)

main()