标签: swampy

我只是初学python并且已经开始使用python 2.7.3 Version.I一直在跟踪Think Python电子书.我陷入了第4章案例研究:界面设计,其中有一个绘制线条的程序.我得到了运行给定代码时出现以下错误.

>执行:

C:\Users\dell\Desktop>python first.py
<swampy.TurtleWorld.Turtle object at 0x017A1650> 
Traceback (most recent call last):
  File "first.py", line 7, in <module>
    fd(bob,100)
  File "C:\Python27\lib\site-packages\swampy\TurtleWorld.py", line 186, in fd
    self.world.canvas.line([p1, p2], fill=self.pen_color)
AttributeError: 'NoneType' object has no attribute 'canvas'`

>脚本

from swampy.TurtleWorld import *
world=TurtleWorld
bob=Turtle()
print bob
fd(bob,100)
lt(bob)
fd(bob,100)
wait_for_user()