[Chicago] Question about accessing dictionary's elements.

Sat Sep 19 20:54:24 CEST 2015

umm i can do skype

On Sat, Sep 19, 2015 at 1:46 PM Lewit, Douglas <d-lewit at neiu.edu> wrote:

> Hey Joshua!  I would LOVE to, but I have classes on Wednesday and Thursday
> evenings.  So.... ???
>
> On Sat, Sep 19, 2015 at 1:30 PM, Joshua Herman <zitterbewegung at gmail.com>
> wrote:
>
>> Hey I'm doing machine learning too why don't you come to one of the
>> python meet ups in Chicago
>>
>> On Sat, Sep 19, 2015 at 12:56 PM Lewit, Douglas <d-lewit at neiu.edu> wrote:
>>
>>> Hi William,
>>>
>>> I'm doing a KNN program (K-Nearest-Neighbors).  I'm attaching what I've
>>> done so far.  It's not complete!  But I've made good progress I think.
>>>  (The program won't work unless you also download the .txt file that the
>>> program uses to read in the data.)
>>>
>>> For this problem the data has to get split into two sets: a training set
>>> (kind of like a control group in an experiment) and the test set (the
>>> experimental group or its equivalent).  I have to use the K smallest
>>> normalized distances to make a guess about which class the records in the
>>> Training Set belong to.  (There are six classes: {1, 2, 3, 5, 6, 7}.
>>> There's no class #4.)
>>>
>>> This problem has given me a massive headache, but I think I'm almost
>>> done with it.  All that's left really is to use one of the algorithms to
>>> make a decision about which class each Test record should be assigned to.
>>>
>>> Thanks for the feedback!
>>>
>>> Best,
>>>
>>> Douglas.
>>>
>>>
>>> On Sat, Sep 19, 2015 at 10:45 AM, William E. S. Clemens <
>>> wesclemens at gmail.com> wrote:
>>>
>>>> I would agree that Jimmy's solution is the correct one for doing this.
>>>> But I would avoid setting up your data structure in this manner. A dict is
>>>> a hash table and it is be extremely fast a looking up a value by key.
>>>>
>>>> You are building an array of the keys to linearly search. This
>>>> operation is going to be slow and will not scale well. If you described
>>>> what this data is and what your trying todo with it. I maybe able to
>>>> suggest a better data structure for storing and accessing it.
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> William Clemens
>>>> Phone: 847.485.9455
>>>> E-mail: wesclemens at gmail.com
>>>>
>>>> On Sat, Sep 19, 2015 at 10:02 AM, Lewit, Douglas <d-lewit at neiu.edu>
>>>> wrote:
>>>>
>>>>> I love it!  Thanks Jim.
>>>>>
>>>>> On Sat, Sep 19, 2015 at 8:09 AM, Jimmy Calahorrano via Chicago <
>>>>> chicago at python.org> wrote:
>>>>>
>>>>>> is more elegant but not sure if is the best option:
>>>>>>
>>>>>>
>>>>>> [A[key] for key in A.keys() if key[0] == 1]
>>>>>>
>>>>>>
>>>>>>
>>>>>> --------------------------------------------
>>>>>> On Sat, 9/19/15, Lewit, Douglas <d-lewit at neiu.edu> wrote:
>>>>>>
>>>>>>  Subject: [Chicago] Question about accessing dictionary's elements.
>>>>>>  To: "The Chicago Python Users Group" <chicago at python.org>
>>>>>>  Date: Saturday, September 19, 2015, 7:43 AM
>>>>>>
>>>>>>  Hi
>>>>>>  guys,
>>>>>>  I have a problem and not
>>>>>>  sure how to address it.  Let's say I have a simple
>>>>>>  dictionary such as.
>>>>>>  A = { (1, 2) : 10, (1, 3) :
>>>>>>  15, (1, 4) : 50, (2, 0) : 2, (2, 5) : 8, (2, 12) : 19
>>>>>>  }
>>>>>>  I would like to access any
>>>>>>  and all tuples whose first value is 1 or let's say 2.
>>>>>>  How would I do that?
>>>>>>  So what I'm trying to
>>>>>>  go for is:
>>>>>>  A[(1, placeholder for any
>>>>>>  int value)] thus giving me all the values that correspond to
>>>>>>  (1, #).  Not really sure how to go about this.  Unless....
>>>>>>  I suppose I could do something like
>>>>>>  this:
>>>>>>  for key in
>>>>>>  A:     if list(key)[0]
>>>>>>  == 1:
>>>>>>  print(A[key])  #### Or whatever I want to do with the
>>>>>>  number.
>>>>>>  Hmmm.... maybe that would
>>>>>>  work, but is there a more "elegant" way to do
>>>>>>  this?  Is there any "pattern matching" in Python
>>>>>>  so that I could do this:
>>>>>>  A[(1, #placeholder for any
>>>>>>  int )]
>>>>>>  Hey, thanks for your
>>>>>>  help.
>>>>>>  By the way, has anyone seen
>>>>>>  the book LEARNING PYTHON by Mark Lutz?  Wow!  Full of
>>>>>>  great information, but the book is HUGE!!!  I'll have
>>>>>>  serious back problems if I carry that thing around in my
>>>>>>  backpack!  There's something about small, lightweight
>>>>>>  books that I really prefer.  (And then there's eBooks,
>>>>>>  but that's a horse of a different color in my
>>>>>>  opinion.)
>>>>>>  Have a great weekend and
>>>>>>  I'm looking forward to some ideas on the above
>>>>>>  problem.  Thanks in advance.
>>>>>>  Best,
>>>>>>  Douglas
>>>>>>  L.
>>>>>>
>>>>>>  -----Inline Attachment Follows-----
>>>>>>
>>>>>>  _______________________________________________
>>>>>>  Chicago mailing list
>>>>>>  Chicago at python.org
>>>>>>  https://mail.python.org/mailman/listinfo/chicago
>>>>>>
>>>>>> _______________________________________________
>>>>>> Chicago mailing list
>>>>>> Chicago at python.org
>>>>>> https://mail.python.org/mailman/listinfo/chicago
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Chicago mailing list
>>>>> Chicago at python.org
>>>>> https://mail.python.org/mailman/listinfo/chicago
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Chicago mailing list
>>>> Chicago at python.org
>>>> https://mail.python.org/mailman/listinfo/chicago
>>>>
>>>>
>>> _______________________________________________
>>> Chicago mailing list
>>> Chicago at python.org
>>> https://mail.python.org/mailman/listinfo/chicago
>>>
>>
>> _______________________________________________
>> Chicago mailing list
>> Chicago at python.org
>> https://mail.python.org/mailman/listinfo/chicago
>>
>>
> _______________________________________________
> Chicago mailing list
> Chicago at python.org
> https://mail.python.org/mailman/listinfo/chicago
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/chicago/attachments/20150919/faf030be/attachment.html>