[Tutor] list objects are unhashable

[Norman Khine]

Thanks,
but where do i replace the x with tuple(x)

Norman

Cédric Lucantis wrote:
> Le Monday 30 June 2008 20:55:36 Norman Khine, vous avez écrit :
>> Hello,
>>
>> I would like to count list items but am not 100% sure how to do it.
>>
>> Here is what I have so far:
>>
>>          for brain in brains:
>>              x = getattr(brain, horizontal)
>>              y = getattr(brain, vertical)
>>              if x and y and (x, y) in table:
>>                  table[(x, y)] += 1
>>                  table[(x, '')] += 1
>>                  table[('', y)] += 1
>>                  table[('', '')] += 1
>>
>> but when I run this, I get the following error on the line:
>>
>> if x and y and (x, y) in table:
>>
>> TypeError: list objects are unhashable
>>
>> where:
>>
>> x = ['airlines-scheduled', 'airport-car-parking']
>>
> 
> lists are not hashable because hashing a mutable type would be dangerous, but 
> tuples are if all their items are hashable too. Just replace x by tuple(x).
>