【实用代码】Python turtle demo解析——汉诺塔（minimal hanoi）

小型汉诺塔的动画，六层塔盘从左边移动到右边。

圆盘就是一个海龟，但是形状设置成了方形。

代码解析：

from turtle import *

# 圆盘
class Disc(Turtle):
    def __init__(self, n):
        Turtle.__init__(self, shape="square", visible=False)
        self.pu()
        # 矩形大小
        self.shapesize(1.5, n*1.5, 2) # square-->rectangle
        # 设置颜色
        self.fillcolor(n/6., 0, 1-n/6.)
        self.st()

# 塔
class Tower(list):
    "Hanoi tower, a subclass of built-in type list"
    def __init__(self, x):
        "create an empty tower. x is x-position of peg"
        self.x = x
    # 加入盘子
    def push(self, d):
        d.setx(self.x)
        d.sety(-150+34*len(self))
        self.append(d)
    # 取出盘子
    def pop(self):
        d = list.pop(self)
        d.sety(150)
        return d

# 汉诺塔算法
def hanoi(n, from_, with_, to_):
    if n > 0:
        hanoi(n-1, from_, to_, with_)
        to_.push(from_.pop())
        hanoi(n-1, with_, from_, to_)

def play():
    onkey(None,"space")
    clear()
    try:
        hanoi(6, t1, t2, t3)
        write("press STOP button to exit",
              align="center", font=("Courier", 16, "bold"))
    except Terminator:
        pass  # turtledemo user pressed STOP

def main():
    global t1, t2, t3
    ht(); penup(); goto(0, -225)   # writer turtle
    # 放置三个塔
    t1 = Tower(-250)
    t2 = Tower(0)
    t3 = Tower(250)
    # make tower of 6 discs
    # 第一个塔加六个盘子
    for i in range(6,0,-1):
        t1.push(Disc(i))
    # prepare spartanic user interface ;-)
    write("press spacebar to start game",
          align="center", font=("Courier", 16, "bold"))
    onkey(play, "space")
    listen()
    return "EVENTLOOP"

if __name__=="__main__":
    msg = main()
    print(msg)
    mainloop()

通过修改参数很容易增加盘子数目，比如增加到20个盘子

from turtle import *

disc_num = 20
# 圆盘
class Disc(Turtle):
    def __init__(self, n):
        Turtle.__init__(self, shape="square", visible=False)
        self.pu()
        # 矩形大小
        self.shapesize(1.1, n*1.1, 1.1) # square-->rectangle
        # 设置颜色
        self.fillcolor(n/disc_num, 0, 1-n/disc_num)
        self.st()

# 塔
class Tower(list):
    "Hanoi tower, a subclass of built-in type list"
    def __init__(self, x):
        "create an empty tower. x is x-position of peg"
        self.x = x
    # 加入盘子
    def push(self, d):
        d.setx(self.x)
        d.sety(-150+20*len(self))
        self.append(d)
    # 取出盘子
    def pop(self):
        d = list.pop(self)
        d.sety(150)
        return d

# 汉诺塔算法
def hanoi(n, from_, with_, to_):
    if n > 0:
        hanoi(n-1, from_, to_, with_)
        to_.push(from_.pop())
        hanoi(n-1, with_, from_, to_)

def play():
    onkey(None,"space")
    clear()
    try:
        hanoi(disc_num, t1, t2, t3)
    except Terminator:
        pass  # turtledemo user pressed STOP

def main():
    global t1, t2, t3
    ht(); penup(); goto(0, -225)   # writer turtle
    tracer(2000)
    # 放置三个塔
    t1 = Tower(-550)
    t2 = Tower(0)
    t3 = Tower(550)
    # make tower of disc_num discs
    # 第一个塔加六个盘子
    for i in range(disc_num,0,-1):
        t1.push(Disc(i))
    # prepare spartanic user interface ;-)
    write("press spacebar to start game",
          align="center", font=("Courier", 16, "bold"))
    onkey(play, "space")
    listen()
    return "EVENTLOOP"

if __name__=="__main__":
    msg = main()
    print(msg)
    mainloop()