Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: Dennis Lee Bieber <wlfraed@ix.netcom.com>
Newsgroups: comp.lang.python
Subject: Re: Considering migrating to Python from Visual Basic 6 for engineering applications
Date: Fri, 19 Feb 2016 08:13:15 -0500
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On Fri, 19 Feb 2016 03:53:03 -0800 (PST), wrong.address.1@gmail.com
declaimed the following:

>
>That is what VB.net seems designed for. I know nothing about Python, and have to decide soon, so I am asking these *very stupid* questions.
>
	I've not done .NET, but surely they haven't removed the ability to read
a full line and then perform string operations on the result to find
fields.

	But in general, for ad-hoc input, scanning of some sort will be
required to locate/parse the values. It becomes much simpler if the input
has a specified structure (fixed columns being traditional).


>The new languages are not designed by engineers or for engineers, so it is likely that what we take for granted may not be easy in Python. It was different when there was no such thing called "computer science" in the 1960s.
>

	There was FORTRAN -- which didn't even have a character string data
type; one used fixed size arrays of individual characters and had to
perform lots of loops to locate and copy "words". Heck, even in the
mid-80s, one of the most used utility functions in the department I was in
was to take a line of user input and split it into a 2-dimensional array
(10 entries of 32 characters max) on white space, just so the rest of the
program could parse the user command input.

	Provide a specification for your input data, and I'm sure almost anyone
here could come up with something to read it.

>2 12.657823 0.1823467E-04 114 0
>3 4 5 9 11
>"Lower"
>278.15

	A block of four lines, white-space delimited:
		Integer, 2 floats, 2 integers
		5 integers
		string with " delimiter
		float

def readBlock(fin):
    #NO ERROR CHECKING INCLUDED
    ln = fin.readline().strip()
    flds = ln.split()
    l1 = [int(flds[0]), float(flds[1]),
          float(flds[2]), int(flds[3]),
          int(flds[4])]
    ln = fin.readline().strip()
    l2 = [int(fld) for fld in ln.split()]
    ln = fin.readline().strip()
    l3 = ln.strip('"')
    ln = fin.readline().strip()
    l4 = float(ln)
    return (l1, l2, l3, l4)

	The "l1 =" line could fail for: less than 5 fields on the input line;
invalid character for int/float data within a field; excess fields will be
ignored. The "l2 =" line could fail for: invalid character for int data; it
will accept any number of integer fields. The "l4 =" could fail for invalid
characters for a float.

	What it returns is a tuple containing a list of 5 (mixed) numerics, a
list of 5 integers, one string, and a float.


>> https://docs.python.org/3/library/re.html.  Or a likely replacement for 
>> the re module https://pypi.python.org/pypi/regex.
>> 
>
>Thanks.
>
>> -- 
>> My fellow Pythonistas, ask not what our language can do for you, ask
>> what you can do for our language.
>> 
>> Mark Lawrence
-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/