Python简单的乌龟程序

Question

我在尝试完成python龟程序时遇到了麻烦。当我尝试输入x和y坐标以及函数的半径值时 t.drawSnowman（x = 25，y = 25，radius = 25）当我输入值时，程序行为不正常。但如果我省略上面的参数而只是使用t.drawSnowman（），程序按预期工作，但我不是能够创建雪人的各种实例。

我真的很想帮忙试图找出如何输入参数并仍然具有程序功能。

这是我的代码

import turtle

class MyTurtle(turtle.Turtle):
""""""


def __init__(self):
    """Turtle Constructor"""
    turtle.Turtle.__init__(self, shape="turtle")

def drawNose(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw nose '''
    self.pendown()
    self.goto(-(radius) * (0.25),(radius * 6)+(radius * 4)+(radius))
    self.goto(0,(radius * 6)+(radius * 4)+(radius)+(radius * (0.25)))
    self.goto((radius) * (0.25),(radius * 6)+(radius * 4)+(radius))
    self.goto(0,(radius * 6)+(radius * 4)+(radius))
    self.penup()

def leftEye(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw left eye'''
    self.pendown()
    self.circle(radius*(.25))
    self.penup()
def rightEye(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw right eye'''
    self.pendown()
    self.circle(radius*(.25))
    self.penup()
def bottomOfHat(self, x=0, y=0, radius = 15, circle_color = "black"):
    ''' draw the long part of the hat at the bottom '''
    self.goto(0,(radius * 6)+(radius * 4)+(radius * 2))
    self.pendown()
    self.goto(-(radius),(radius * 6)+(radius * 4)+(radius * 2))
    self.goto(-(radius),(radius * 6)+(radius * 4)+(radius * 2)+(radius * (0.5)))
    self.goto(radius,(radius * 6)+(radius * 4)+(radius * 2)+(radius * (0.5)))
    self.goto(radius,(radius * 6)+(radius * 4)+(radius * 2))
    self.goto(0,(radius * 6)+(radius * 4)+(radius * 2))
    self.penup()

def topOfHat(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw the top bigger part of the hat'''
    self.goto(radius*(.75),(radius * 6)+(radius * 4)+(radius * 2)+(radius * (0.5)))
    self.pendown()
    self.goto(radius*(.75),(radius * 6)+(radius * 4)+(radius * 2)+(radius * 2))
    self.goto(-(radius)*(.75),(radius * 6)+(radius * 4)+(radius * 2)+(radius * 2))
    self.goto(-(radius)*(.75),(radius * 6)+(radius * 4)+(radius * 2)+(radius * (0.5)))

def bottomCircle(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draws the bottom circle'''
    self.pendown()
    self.circle(radius * 3)
    self.penup()
def middleCircle(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw the middle circle'''
    self.pendown()
    self.circle(radius * 2)
    self.penup()
def topCircle(self, x=0, y=0, radius = 15, circle_color = "black"):
    '''draw the top circle'''
    self.pendown()
    self.circle(radius)
    self.penup()
def drawSnowman(self, x=0, y=0, radius = 15, circle_color = "black"):
    self.bottomCircle()
    self.goto(0,radius * 6)
    self.middleCircle()
    self.goto(0,(radius * 6)+(radius * 4))
    self.topCircle()
    self.goto(-(radius) * (0.5),(radius * 6)+(radius * 4)+(radius))
    self.leftEye()
    self.goto((radius) * (0.5),(radius * 6)+(radius * 4)+(radius))
    self.rightEye()
    self.goto(0,(radius * 6)+(radius * 4)+(radius))
    self.drawNose()
    self.bottomOfHat()
    self.topOfHat()



t = MyTurtle()
t.hideturtle()
radius = 15
t.drawSnowman(x = 25,y = 25,radius = 25)

这是我使用参数时雪人的照片 t.drawsnowman（x = 25 y = 25 radius = 25）

当我输入没有参数时，这是雪人t.drawsnowman（）

Answer 1

尝试一步一步地找出代码实际执行的操作（或使用调试器）。

• 如果您致电t.drawSnowman()，radius将15。
• 您致电bottomCircle()，其中将绘制一个半径为radius * 3 = 45
的圆圈
• 您在y轴上移动radius * 6 = 90（您现在“在圈子的顶部”）
• 您致电middleCircle()这将是一个半径为radius * 2 = 30的圆圈
• ...

现在，看看如果使用参数调用函数会发生什么：

• 如果您致电t.drawSnowman(x = 25,y = 25,radius = 25)，radius将25。
• 您致电bottomCircle()，其中会绘制一个半径为radius * 3 = 45的圆圈。请注意局部变量radius是15的方式，因为它是该参数的默认值，并且您没有将传递给drawSnowman的值传递给bottomCircle方法
• 您在y轴上移动radius * 6 = 150（您现在远离的圆圈）
• 您致电middleCircle()，其中半径为radius * 2 = 30的圆圈。请注意局部变量radius也是15。
• ...

所以，问题在于你传递了radius的值，但是你只使用该值来移动drawSnowman中的乌龟，而不是在任何其他函数中移动乌龟。