Renumbering

[John Machin]

On Sep 3, 6:57 am, "Francesco Pietra" <chiendar... at gmail.com> wrote:
> Hi;
>
> I would like to renumber, starting from 1, column 6 (i.e, 428 become
> 1, 429 becomes 2, etc for a very long list)
>
> ATOM   3424  N   LEU B 428     143.814  87.271  77.726  1.00115.20       2SG3426
[snip]
> ATOM   3437  O   SER B 429     144.543  83.756  79.676  1.00134.86       2SG3439
>
> Distinctive character is column 5, i.e., it must be set that only
> lines containing "B" should be renumbered.
>
> As you can see, the number of lines for a particular value in column 6
> changes from situation to situation, and may even be different for the
> same name in column 4. For example, LEU can have a different number of
> lines depending on the position of this amino acid (leucine).

The above paragraph is extremely unclear.

>
> Thanks for help

You haven't asked a question, and haven't given any background. What
is your experience with Python? Any other language? Are you expecting
somebody to write a script for you, or just give you a few hints? Is
this homework? Have you put any effort into trying to write a script
yourself? Etc etc etc