[Tutor] A couple of somewhat esoteric questions

[Dave Angel]

Dave Angel <davea at davea.name> Wrote
 in message:
> "Clayton Kirkwood" <crk at godblessthe.us> Wrote in message:
>> 
>> 
>> !-----Original Message-----
>> !From: Tutor [mailto:tutor-bounces+crk=godblessthe.us at python.org] On
>> !Behalf Of Steven D'Aprano
> ...
>> 
>> For clarification, a key only has one value which can be changed. 
> 
> No, because the key has to be immutable, like a string or an int.

My error for reading your statement wrong.

> 
>> Multiple
>> keys can have the same value (hopefully not to the same memory location,
>> because one would usually not want the change of one key's value to alter
>> another key's value. As to the hash table, yes, I agree that this would be
>> one to many, hence the chains.
> 
> Memory locations are an implementation detail. We're talking in
>  this paragraph about keys and values. A value is an object, the
>  dict provides a one-way mapping from immutable key to an
>  arbitrary value object. If the value objects happen to be
>  immutable,  it makes no difference if a program uses the same
>  value for multiple keys. If the values are not immutable,  python
>  makes no assurance whether two values are equal, or identical. If
>  the latter is undesirable for a particular use, it's up to the
>  application logic to prevent it. It's probably more often useful
>  than problematic. Python makes no such assurances.
>  
> 
> 
> 
> 
>> !Can you give a concrete example of what you're trying to do?
>> 
>> The changing of the order is necessary when you want numeric indexing, say
>> for columns or rows.
>> 
> 
> No idea how this relates to dicts, which have no order, nor rows
>  nor columns. Make it concrete.
> 
> 
> -- 
> DaveA
> 
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-- 
DaveA