Python与龟的同心正方形

时间:2015-04-07 19:35:45

标签: python turtle-graphics

尝试用Turtle在python中制作同心方块。这是我的尝试:

import turtle
def draw_square(t, size):
   for i in range(4):
       t.forward(size)
       t.left(90)
wn = turtle.Screen()
dan = turtle.Turtle()

sizevar = 1
for i in range(10):
   draw_square(dan,sizevar)
   sizevar += 20
   dan.penup()
   dan.backward(sizevar/ 2)
   dan.right(90)
   dan.forward(sizevar / 2)
   dan.left(90)
   dan.pendown()

我不确定为什么他们不是同心的,我的dan.backward(sizevar/2)dan.forward(sizevar/2)行似乎将广场向下移动到左侧太多了?

2 个答案:

答案 0 :(得分:1)

应该是这样的:

import turtle
def draw_square(t, size):
   for i in range(4):
       t.forward(size)
       t.left(90)
wn = turtle.Screen()
dan = turtle.Turtle()
sizevar = 1
for i in range(10):
   draw_square(dan, sizevar)
   sizevar += 20
   dan.penup()
   dan.backward(10)
   dan.right(90)
   dan.forward(10)
   dan.left(90)
   dan.pendown()

每个方格仅比前一个方格宽10个像素。

答案 1 :(得分:1)

同心方块要求使用递归算法(而不是迭代):

import turtle

def draw_square(t, size):
    for i in range(4):
        t.forward(size)
        t.left(90)

def recursive_draw(t, x, y, size):
    if (size < 200):
        t.penup()
        t.goto(x, y)
        t.pendown()
        draw_square(t, size)
        x -= 10
        y = x
        size += 20
        recursive_draw(t, x, y, size)

wn = turtle.Screen()
dan = turtle.Turtle()
recursive_draw(dan, 0, 0, 1)

以这种方式解释代码似乎更容易:

基本情况:尺寸不得超过200 接近策略:将规模增加20倍