[Tutor] minor display issue with python dictionaries

[Joel Goldstick]

On Sun, Nov 24, 2013 at 11:03 AM, Reuben <reuben.dlink at gmail.com> wrote:
> Hi,
>
> ##########################################
>>>>
>>>> new_dict = {'a':10, 'b' :20, 'c': 30,'d' : 40}
>>>>
>>>>
>>>> print new_dict
> {'a': 10, 'c': 30, 'b': 20, 'd': 40}
>>>>
>
>
> #########################################
>
>
> From the above output, I see key 'c' is at third position during input, but
> while displaying the output it is displayed at second position
>
> Although, I dont see any impact of it since we mainly refer to dictionary
> values only using "keys"  -- but just for curiosity why is this position
> change?
>
> Regards,
> Reuben
>
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The key is the way to the value.  Depending on the implementation,
python might find the value by different algorithms.  Sometimes people
call dictionaries 'hashes', which I believe refers to a method of
indexing that does some algorithm on the key to get the value
location.  This is for speed and for space savings in memory.

So, sometimes you might see a dictionary displayed in the order you
entered it, but sometimes not.


-- 
Joel Goldstick
http://joelgoldstick.com