dict: keys() and values() order guaranteed to be same?

Stefan Behnel stefan_ml at behnel.de
Mon Jul 23 13:58:37 CEST 2012


Philipp Hagemeister, 23.07.2012 13:40:
> On 07/23/2012 01:23 PM, Henrik Faber wrote:
>> With an arbitrary dictionaty d, are d.keys() and d.values()
>> guaraneed to be in the same order?
> 
> Yes. From the documentation[1]:
> 
> If items(), keys(), values(), iteritems(), iterkeys(), and itervalues()
> are called with no intervening modifications to the dictionary, the
> lists will directly correspond.
> 
> [1] http://docs.python.org/library/stdtypes.html#dict.items

Interesting. I wonder if other implementations like Jython and PyPy really
adhere to this official guarantee. At least Jython has the same paragraph
in its documentation and I would expect that PyPy follows it as well.

http://www.jython.org/docs/library/stdtypes.html#mapping-types-dict

Maybe this guarantee is just easy enough to build on the given
implementation details of a platform that it's a common property. Iteration
over data structures should tend to be deterministic, after all.

Stefan





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