[Tutor] Fwd: for loop results into list

[Mike Beatty]

Should have sent this to the list too


---------- Forwarded message ----------
From: Micheal Beatty <mikelbt at gmail.com>
Date: Sun, Sep 5, 2010 at 2:38 PM
Subject: Re: [Tutor] for loop results into list
To: Andre Engels <andreengels at gmail.com>


 On 09/05/2010 02:16 PM, Andre Engels wrote:
>
> On Sun, Sep 5, 2010 at 8:51 PM, Micheal Beatty<mikelbt at gmail.com>  wrote:
>>
>>  On 09/05/2010 01:26 PM, Evert Rol wrote:
>>>>
>>>> Hello all,
>>>>
>>>> I'm having a little problem figuring out how to accomplish this simple
>>>> task. I'd like to take a list of 6 numbers and add every permutation of
>>>> those numbers in groups of four. For example for 1, 2, 3, 4, 5, 6 add 1 + 1
>>>> + 1 +1 then 1 + 1 + 1 +2 etc. until reaching 6 + 6 + 6 + 6. Using a for
>>>> loop, that was the easy part, now I'd like to take the results and count the
>>>> number of times each number occurs.
>>>> My problem occurs when I try to create a list from the results of the for
>>>> loop, it puts each individual number into its own list. I've looked
>>>> everywhere for the solution to this and can find nothing to help.
>>>>
>>>> Any suggestions would be much appreciated
>>>
>>> If you had some code, that would be very helpful. Now it's a bit of
>>> guesswork what exactly you have (code tends to be clearer than a full
>>> paragraph or two of text).
>>> At least, I currently don't understand what your problem is (or what your
>>> for-loop involves).
>>> Eg, are you looping and calling a function recursively, do you have four
>>> nested loops (or nested list comprehensions)? Or some other convenient loop
>>> to step through all combinations?
>>>
>>> Anway, if you have a recent Python version (2.7 or 3.1), the itertools
>>> module provides a handy utiity:
>>> http://docs.python.org/py3k/library/itertools.html#itertools.combinations_with_replacement
>>> Eg,
>>>
>>>>>> map(sum, combinations_with_replacement(range(1,7), 4))
>>>
>>> [4, 5, 6, 7, 8, 9, 6, 7, 8, 9, 10, 8, 9, 10, 11, 10, 11, 12, 12, 13, 14,
>>> 7, 8, 9, 10, 11, 9, 10, 11, 12, 11, 12, 13, 13, 14, 15, 10, 11, 12, 13, 12,
>>> 13, 14, 14, 15, 16, 13, 14, 15, 15, 16, 17, 16, 17, 18, 19, 8, 9, 10, 11,
>>> 12, 10, 11, 12, 13, 12, 13, 14, 14, 15, 16, 11, 12, 13, 14, 13, 14, 15, 15,
>>> 16, 17, 14, 15, 16, 16, 17, 18, 17, 18, 19, 20, 12, 13, 14, 15, 14, 15, 16,
>>> 16, 17, 18, 15, 16, 17, 17, 18, 19, 18, 19, 20, 21, 16, 17, 18, 18, 19, 20,
>>> 19, 20, 21, 22, 20, 21, 22, 23, 24]
>>>
>>> seems to do what you want.
>>>
>>> But, I'd still say to adopt your own code first, and when you've learned
>>> from that, just use the one-liner above. You're most welcome to ask your
>>> question, best done in combination with code, actual output and expected
>>> output. Then we can point you in the right direction.
>>>
>>> Cheers,
>>>
>>>   Evert
>>>
>> Thanks Evert, here is the code.
>>
>>
>> fourdsix = [1, 2, 3, 4, 5, 6]
>> for i in fourdsix:
>>    for j in fourdsix:
>>        for k in fourdsix:
>>            for l in fourdsix:
>>                fourdsix_result = [i, j, k, l]
>>                attribs = sum(fourdsix_result) - min(fourdsix_result)
>>                print attribs
>>
>> This gives me the proper results, now it's just a matter of getting it into
>> a list so I can further work with the data.
>> I've tried the following
>> attrib_list = [attribs]
>>
>> and
>> attrib_list = []
>> attrib_list.append(attribs)
>> print attrib_list
>>
>> but these both only create a list of the last number.
>
> Put the attrib_list = [] before the beginning of the outer loop, and
> it should work as intended. Now you are creating a new list each time,
> which is not what you want.
>
>
>
This gets me close, as it puts the results together into a list but it
goes through every set of permutations and gives me a list.
e.g.
[3]
[3, 4]
[3, 4, 5]
[3, 4, 5, 6]
[3, 4, 5, 6, 7] and so on