Scope, type and UnboundLocalError

[Bruno Desthuilliers]

Paddy a écrit :
> Frank Millman wrote:
> 
>>Paddy wrote:
>>
>>>Hi,
>>>I am trying to work out why I get UnboundLocalError when accessing an
>>>int from a function where the int is at the global scope, without
>>>explicitly declaring it as global but not when accessing a list in
>>>similar circumstances.
>>>
>>
>>With the statement 'm = m + 1', as m is assigned to on the LHS, it is
>>deemed to be local, but as m does not yet have a value on the RHS, you
>>get Unbound Local Error.
>>
>>With the statement 'n[0] = n[0] + 1', n is not being assigned to, as it
>>is mutable. Therefore Python looks in the global namespace, finds n
>>there, and uses it successfully.
>>
>>My 2c
>>
>>Frank Millman
> 
> So, to paraphrase to test my understanding:
> 
> in the statement: ' n[0] = n[0] + 1' it is the object referenced by the
> name n that is being assigned to rather than n itself, so n is not
> 'tagged' as a local variable by the LHS of the assignment.

Nope. You got it plain wrong - cf my answer to Frank in this thread.

> 
> Thanks Frank. all is is now clear :-)

It is obviously not.