Inverse of dict(zip(x,y))

[Tino Wildenhain]

Piet van Oostrum wrote:
>>>>>> Andre Engels <andreengels at gmail.com> (AE) wrote:
> 
>> AE> On Wed, Mar 4, 2009 at 11:02 AM, lone_eagle <icymist at gmail.com> wrote:
>>>> Can someone suggest a easy method to do the inverse of dict(zip(x,y))
>>>> to get two lists x and y?
>>>>
>>>> So, if x and y are two lists, it is easier to make a dictionary using
>>>> d = dict(zip(x,y)), but if I have d of the form, d = {x1:y1,
>>>> x2:y2, ...}, what is there any trick to get lists x = [x1, x2, ...]
>>>> and y = [y1, y2, ...]
> 
>> AE> x = d.keys()
>> AE> y = [d[e] for d in x]
> 
>> AE> y = d.values() might also work, but I am not sure whether d.keys() and
>> AE> d.values() are guaranteed to use the same order.
> 
> Yes, they are if the dictionary is not changed in the meantime (not even
> inserting and removing the same thing). See the library documentation,
> section dict.

Still I'd like to see an application where this really matters (that
keys() and values() match in order)

Tino
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