[Tutor] Fwd: how to sort the file out

[lina]

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 that it's just a matter of writing back to the file, easy peasy.
>
> HTH,
> Hugo
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-- 
Best Regards,

lina