Question

每次单击时，我都尝试用更改颜色来制作正方形。但是当我运行它时，它只会填充红色。如何每次更改颜色？

import turtle
t= turtle.Turtle()
s=turtle.Screen()
colors = ["red","orange","yellow","green","blue","indigo","purple"]
n=0

def square(x,y):
    t.penup()
    t.goto(x,y)
    t.pendown()
    t.color(colors[n])
    t.begin_fill()   
    for i in range(4):
        t.fd(90)
        t.lt(90)
    t.end_fill()
    t.penup()
if s.onscreenclick(square) == True:
    n+=1

Answer 1

您缺少对s.mainloop()的呼叫。而且，如果您希望n每次单击都更改，请在square()函数中将其声明为全局变量，并在完成绘制后对其进行递增。如果n大于len(colors)，请不要忘记将其重置为零。

对s.onscreenclick()的调用告诉乌龟“如何处理点击”（在这种情况下，通过调用square()），因此您无需放入if声明。

import turtle
t= turtle.Turtle()
s=turtle.Screen()
colors = ["red","orange","yellow","green","blue","indigo","purple"]
n=0

def square(x,y): # draw a square at (x,y)
    global n # use the global variable n
    t.penup()
    t.goto(x,y)
    t.pendown()
    t.color(colors[n])
    t.begin_fill()
    for i in range(4):
        t.fd(90)
        t.lt(90)
    t.end_fill()
    t.penup()
    n = (n+1) % len(colors) # change the colour after each square

s.onscreenclick(square) # whenever there's a click, call square()

s.mainloop() # start looping

最后，请确保read this，因为这是您第一次使用StackOverflow。

Answer 2

我宁愿使用itertools中的cycle()，而不是使用全局计数器和模数运算，而只是继续重复该列表：

from turtle import Turtle, Screen
from itertools import cycle

colors = cycle(["red", "orange", "yellow", "green", "blue", "indigo", "purple"])

def square(x, y):
    screen.onscreenclick(None)  # disable handler inside handler

    turtle.penup()
    turtle.goto(x, y)
    turtle.pendown()

    turtle.color(next(colors))

    turtle.begin_fill()
    for _ in range(4):
        turtle.forward(75)
        turtle.left(90)
    turtle.end_fill()

    turtle.penup()

    screen.onscreenclick(square)

screen = Screen()
turtle = Turtle()

screen.onscreenclick(square)

screen.mainloop()

还请注意，我在处理程序的实现中禁用了onscreenclick()处理程序，因此当上一个正方形仍在绘制时，用户无法单击，这会导致混乱的结果。

Python通过使用列表颜色制作海龟图形

2 个答案: