[Octave-bug-tracker] [bug #34734] problems with latest strread (newlines, spaces and commas)

[Kris Thielemans]

URL:
  <http://savannah.gnu.org/bugs/?34734>

                 Summary: problems with latest strread (newlines, spaces and
commas) 
                 Project: GNU Octave
            Submitted by: krthie
            Submitted on: Thu 03 Nov 2011 12:25:29 GMT
                Category: Libraries
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Kris Thielemans
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

This was originally discussed on the Octave- general mailing list (See the
thread
http://octave.1599824.n4.nabble.com/problems-with-latest-strread-comma-delimiters-tt3913839.html#a3919252).
Some behaviour reported here is related to bug #34713
(https://savannah.gnu.org/bugs/index.php?34713)


I'm trying to use textread but had trouble on Octave 3.4.2 (built from source
on Ubuntu 11.04). Therefore, I downloaded the latest strread.m from mercurial,
renaming it to newstrread.m. 

However, newstrread behaves unexpectly with commas/spaces and newlines.


    octave>  [a1,a2]=newstrread("1,2\n3,4\n", '%f%f', 'delimiter',',')
    a1 =
       1
       4
    a2 =
        23
       NaN


The newline was not considered as a "new record" and just ignored. Instead,
the 3.2.4 version of strread reads this correctly:

    octave>  [a1,a2]=strread("1,2\n3,4\n", '%f%f', 'delimiter',',')
    a1 =
       1
       3
    a2 =
       2
       4 


Here's another case where both the 3.2.4 and new strread (and textread) ignore
some unknown characters, which causes rather strange results:

    octave>  [a1,a2]=newstrread("1a2\n3,4", '%f%f')
    a1 = NaN
    a2 =  34

Returning a NaN for the first line is ok, but ignoring the comma is wrong (see
bug #34713). 

In the discussion in the email thread, it appeared that this behaviour is
partly due to the fact that currently strread doesn't interpret a new line as
a new "record", which seems incorrect.

Another example without newlines

octave> [a1,a2]=newstrread("1     2, 3 4",'%f%f','delimiter','t')
a1 =  1234
a2 = [](0x1) 

IMO, whitespace and commas should not be ignored "inside" a field (whitespace
should of course be ignored between fields when using the above format
specifier).








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