[Tutor] Fwd: how to sort the file out

[lina]

On Wed, Sep 7, 2011 at 2:57 PM, lina <lina.lastname at gmail.com> wrote:
> On Wed, Sep 7, 2011 at 2:25 PM, Hugo Arts <hugo.yoshi at gmail.com> wrote:
>> forgot to forward this to list, sorry.
>>
>>
>> ---------- Forwarded message ----------
>> From: Hugo Arts <hugo.yoshi at gmail.com>
>> Date: Wed, Sep 7, 2011 at 8:24 AM
>> Subject: Re: [Tutor] how to sort the file out
>> To: lina <lina.lastname at gmail.com>
>>
>>
>> On Wed, Sep 7, 2011 at 8:16 AM, lina <lina.lastname at gmail.com> wrote:
>>> On Wed, Sep 7, 2011 at 1:28 PM, Hugo Arts <hugo.yoshi at gmail.com> wrote:
>>>> I was assuming that the numbers were field 1, and the letter/number
>>>> combinations were field 2. If I understand him correctly, he wants the
>>>
>>> Yes.
>>>
>>>> lines in file 2 to be arranged such that the order of field two is the
>>>> same as it is in file 1. In that case, you can do it with one sexy
>>>> sort() call (and a little preprocessing to load the files), but I
>>>> don't want to get all into explain and then realize he wants something
>>>> totally different.
>>> You understand right.
>>>
>>
>> Well, it is fairly simple. You grab field2 from file1, and put all the
>> items into a list (should be easy right? open(), readlines(), split(),
>> grab second item). Then, you grab file2 as a list of tuples (same
>> procedure as the first file, but you just put the results of split()
>> right into the list. Then you sort with a key like so:
>>
>> list2.sort(key=lambda x: list1.index(x[1]))
>>
>> You see? For each item in the second list, we grab field 2, and look
>> up what index it has in list1. Then we use that index as the sort key.
>> That way they'll be sorted like file1 is.
>
> not easy to me.
>
> Sign ... I may do it by hand, cut and pasta following the orders.

After overcoming the nearly-give-up frustration, I finally see the
deadly-beautiful results.

It's so BEAUTIFUL.

amazing ...



>>
>> After that it's just a matter of writing back to the file, easy peasy.
>>
>> HTH,
>> Hugo
>> _______________________________________________
>> Tutor maillist  -  Tutor at python.org
>> To unsubscribe or change subscription options:
>> http://mail.python.org/mailman/listinfo/tutor
>>
>
>
>
> --
> Best Regards,
>
> lina
>



-- 
Best Regards,

lina