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Groups > comp.lang.python > #103276

Re: Considering migrating to Python from Visual Basic 6 for engineering applications

From Christian Gollwitzer <auriocus@gmx.de>
Newsgroups comp.lang.python
Subject Re: Considering migrating to Python from Visual Basic 6 for engineering applications
Date 2016-02-20 20:21 +0100
Organization A noiseless patient Spider
Message-ID <naae5n$3g9$1@dont-email.me> (permalink)
References (9 earlier) <9e57761f-26e1-41c5-8e71-23800de1fdd3@googlegroups.com> <mailman.40.1455881073.2289.python-list@python.org> <729e6513-4d1d-4b9b-be8b-4b7664abac2e@googlegroups.com> <56c81b9f$0$1585$c3e8da3$5496439d@news.astraweb.com> <22994701-0b2b-42ba-9ae5-36b8c428150b@googlegroups.com>

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Am 20.02.16 um 19:45 schrieb wrong.address.1@gmail.com:
> On Saturday, 20 February 2016 09:54:15 UTC+2, Steven D'Aprano  wrote:
>> To answer your question "Do I need something fancy...?", no, of course not,
>> reading a line of numbers from a text file is easy.
>>
>> with open("numbers.txt", "r") as f:
>>      for line in f:
>>          numbers = [int(s) for s in split(line)]
>>
>
> This looks good enough. This does not seem complicated (although I still understand almost nothing of what is written). I was simply not expressing myself in a way you people would understand.
>
>>
>> will read and convert integer-valued numbers separated by whitespace like:
>>
>>      123 654 9374 1 -45 3625
>>
>>
>> one line at a time. You can then collate them for later use, or process them
>> as you go. If they're floating point numbers, change the call to int() to a
>> call to float().
>>
>
> And I guess if the first three numbers are integers and the fourth is a float, then also there must be some equally straightforward way.

If you know in advance, what you expect, then it is easy. Most people 
who gave you answers assumed that you have a messy file and don't know 
if an int or float follows, and you want a program which decides by 
itself whether to read an int, float or string.

Whereas, if the format is fixed, for 3 ints and 1 float, you could do:

str='1 2 3 3.14159' # some example
fmt=(int,int,int,float) # define format
a,b,c,d=[type(x) for (type,x) in zip(fmt, str.split())]

It's one line, but it might look involved and actually it uses a list 
comprehension, tuple unpacking and first class functions, so it's 
certainly not comprehensible from the first Python lesson. Another 
alternative would be sscanf. This is a 3rd party module which simulates 
C sscanf, optimized more or less for this kind of number parsing:

https://hkn.eecs.berkeley.edu/~dyoo/python/scanf/

After installing that, you can do:

from scanf import sscanf
str='1 2 3 3.14159'
a,b,c,d=sscanf(str, '%d %d %d %f')

whereby '%d' means integer and '%f' is float. sscanf also handles 
fixed-width columns which you often get from Fortran programs.

	Christian

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Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-17 11:49 -0800
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications sohcahtoa82@gmail.com - 2016-02-17 12:25 -0800
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-02-17 20:54 +0000
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications Ray Cote <rgacote@appropriatesolutions.com> - 2016-02-17 16:13 -0500
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications paul.hermeneutic@gmail.com - 2016-02-17 14:18 -0700
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications William Ray Wing <wrw@mac.com> - 2016-02-17 16:27 -0500
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 00:17 -0800
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-02-18 10:09 +0000
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-18 21:16 +1100
        Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 03:11 -0800
          Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-18 22:32 +1100
            Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 07:49 -0800
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-19 03:06 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 09:49 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dietmar Schwertberger <maillist@schwertberger.de> - 2016-02-18 21:37 +0100
              RE: Considering migrating to Python from Visual Basic 6 for engineering applications Dan Strohl <D.Strohl@F5.com> - 2016-02-18 16:24 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 09:58 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Tim Chase <python.list@tim.thechases.com> - 2016-02-18 13:18 -0600
            Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-19 11:30 +1100
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-19 11:57 +1100
              Ohnoes significant whitespace (was: Considering migrating to Python from Visual Basic 6 for engineering applications) Ben Finney <ben+python@benfinney.id.au> - 2016-02-19 12:03 +1100
                Re: Ohnoes significant whitespace Marko Rauhamaa <marko@pacujo.net> - 2016-02-19 08:36 +0200
                Re: Ohnoes significant whitespace (was: Considering migrating to Python from Visual Basic 6 for engineering applications) Grant Edwards <invalid@invalid.invalid> - 2016-02-19 14:57 +0000
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-19 02:14 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-19 21:18 +1100
          Re: Considering migrating to Python from Visual Basic 6 for engineering applications Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-02-18 15:20 +0000
            Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 07:33 -0800
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-02-18 15:47 +0000
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications William Ray Wing <wrw@mac.com> - 2016-02-18 10:59 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 09:38 -0800
              RE: Considering migrating to Python from Visual Basic 6 for engineering applications Dan Strohl <D.Strohl@F5.com> - 2016-02-18 16:00 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 09:44 -0800
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications Tim Chase <python.list@tim.thechases.com> - 2016-02-18 13:28 -0600
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-19 02:47 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-02-19 11:23 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-19 03:53 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-02-19 08:13 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-20 18:54 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-20 10:45 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Christian Gollwitzer <auriocus@gmx.de> - 2016-02-20 20:21 +0100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Tony van der Hoff <tony@vanderhoff.org> - 2016-02-19 11:34 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Tim Chase <python.list@tim.thechases.com> - 2016-02-19 07:40 -0600
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-19 10:14 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-19 23:06 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Larry Hudson <orgnut@yahoo.com> - 2016-02-19 23:49 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-20 10:38 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Larry Hudson <orgnut@yahoo.com> - 2016-02-20 23:28 -0800
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-21 13:16 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-22 00:54 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-02-21 17:08 +0200
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-21 16:16 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-02-21 23:52 +0200
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-21 23:05 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-02-22 10:50 +0200
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-22 12:24 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-02-21 21:19 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-22 21:46 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-02-22 13:39 +0200
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Random832 <random832@fastmail.com> - 2016-02-22 09:49 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-22 16:21 +0000
                Re: Considering migrating to Python from Visual Basic 6 for   engineering applications Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-02-23 10:45 +1300
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Christian Gollwitzer <auriocus@gmx.de> - 2016-02-21 16:21 +0100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Tim Chase <python.list@tim.thechases.com> - 2016-02-21 12:19 -0600
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-02-21 21:40 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-22 22:16 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-22 12:51 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-23 00:09 +1100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-02-21 13:39 -0500
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Peter Otten <__peter__@web.de> - 2016-02-19 15:58 +0100
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Matt Wheeler <m@funkyhat.org> - 2016-02-19 17:05 +0000
                Re: Considering migrating to Python from Visual Basic 6 for engineering applications Roel Schroeven <roel@roelschroeven.net> - 2016-02-20 23:28 +0100
          Re: Considering migrating to Python from Visual Basic 6 for engineering applications Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-02-19 01:07 +0000
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications wxjmfauth@gmail.com - 2016-02-18 01:49 -0800
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications William Ray Wing <wrw@mac.com> - 2016-02-18 09:07 -0500
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-18 07:35 -0800
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-19 12:06 +1100
        Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-19 03:11 -0800
          Re: Considering migrating to Python from Visual Basic 6 for engineering applications Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-02-19 08:27 -0500
            Re: Considering migrating to Python from Visual Basic 6 for engineering applications Steven D'Aprano <steve@pearwood.info> - 2016-02-20 12:13 +1100
              Re: Considering migrating to Python from Visual Basic 6 for engineering applications William Ray Wing <wrw@mac.com> - 2016-02-19 22:28 -0500
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-19 15:34 +0000
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-20 02:43 +1100
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications Grant Edwards <invalid@invalid.invalid> - 2016-02-19 16:04 +0000
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications Grant Edwards <invalid@invalid.invalid> - 2016-02-19 15:59 +0000
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications BartC <bc@freeuk.com> - 2016-02-19 16:32 +0000
        Re: Considering migrating to Python from Visual Basic 6 for engineering applications Chris Angelico <rosuav@gmail.com> - 2016-02-20 03:49 +1100
        Re: Considering migrating to Python from Visual Basic 6 for engineering applications Grant Edwards <invalid@invalid.invalid> - 2016-02-19 18:03 +0000
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications Denis Akhiyarov <denis.akhiyarov@gmail.com> - 2016-02-19 20:58 -0800
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-20 10:50 -0800
      Re: Considering migrating to Python from Visual Basic 6 for engineering applications Denis Akhiyarov <denis.akhiyarov@gmail.com> - 2016-02-22 00:02 -0800
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications Mike S <mscir@yahoo.com> - 2016-02-20 19:52 -0800
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications wxjmfauth@gmail.com - 2016-02-20 01:46 -0800
  Re: Considering migrating to Python from Visual Basic 6 for engineering applications nholtz <nholtz@cee.carleton.ca> - 2016-02-20 08:22 -0800
    Re: Considering migrating to Python from Visual Basic 6 for engineering applications wrong.address.1@gmail.com - 2016-02-20 10:47 -0800

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