如何用“try”语句捕获 TurtleGraphicsError

Question

如果您在 Python 的 Turtle Graphics 中输入了无法识别的颜色，系统会返回给您，例如：

Traceback (most recent call last):
  File "C:\Python33\turtle\ex21-starafterstar.py", line 18, in <module>
    color(outline,fillcol)      # Set pen and fill colors
  File "<string>", line 1, in color
  File "C:\Python33\lib\turtle.py", line 2208, in color
    pcolor = self._colorstr(pcolor)
  File "C:\Python33\lib\turtle.py", line 2688, in _colorstr
    return self.screen._colorstr(args)
  File "C:\Python33\lib\turtle.py", line 1150, in _colorstr
    raise TurtleGraphicsError("bad color string: %s" % str(color))
turtle.TurtleGraphicsError: bad color string: yucky brown

由此可以推断，在 'try 语句中捕获此类错误的方法是编写代码：

try:
    outline = input("Enter the outline color  > ")
    pencolor(outline)
    break
except TurtleGraphicsError:
    print("Sorry. I don't recognise that color.")

但这不起作用。它会产生以下错误：

Traceback (most recent call last):
  File "C:/Python33/turtle/ex28-star5coloredtry.py", line 17, in <module>
    except TurtleGraphicsError:
NameError: name 'TurtleGraphicsError' is not defined

因此，我的问题是，Turtle Graphics 错误的错误类的名称是什么？

Answer 1

如错误消息所述，名称TurtleGraphicsError 未在该范围内定义。它在turtle 包中定义。您可以像这样导入它：

from turtle import TurtleGraphicsError

或使用它的限定名称

import turtle
try:
    ...
except turtle.TurtleGraphicsError:
    print(...)