On 10/27/07, David Joyner <[EMAIL PROTECTED]> wrote:
> Is the following a feature  or a bug?
>
> sage: set([1,2])
> set([1, 2])
> sage: set([[1],[2]])
> ---------------------------------------------------------------------------
> <type 'exceptions.TypeError'>             Traceback (most recent call last)
>
> /Users/wdj/sagefiles/sage-2.8.2/<ipython console> in <module>()
>
> <type 'exceptions.TypeError'>: list objects are unhashable
>
> (Set also does this).

Elements of Python sets must be immutable.  I wouldn't call it either
a feature or a bug.  Perhaps it's a defficiency, though sets of lists
would be very inefficient in Python, if they were limited.   Anyway, you should
use tuples instead of lists if you want sets of them.

 -- William

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