From bug-octave-request at bevo dot che dot wisc dot edu  Fri Jul 21 20:58:55 2000
Subject: Re: str2mat does not accept []
From: pkienzle at kienzle dot powernet dot co dot uk (Paul Kienzle)
To: bug-octave at bevo dot che dot wisc dot edu
Date: Fri, 21 Jul 2000 20:59:10 -0500 (CDT)

Okay, matlab accepts both [] and '', and treats them as equivalent.
Actually, matlab's str2mat seems to have an implicit setstr on all
its arguments:

	>> str2mat(65,'B')
	ans =
	A
	B


Unfortunately, this means that in either case my code example won't
work: I will end up with a blank string at the head of my list of
strings.  The solution is a new function, strvcat, which in matlab
does vertical concatenation but ignores empty matrices.  I'll repost
patches shortly.


From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
>On  9-Jun-2000, Paul Kienzle <pkienzle at kienzle dot powernet dot co dot uk> wrote:
>
>| To: bug-octave at bevo dot che dot wisc dot edu
>| Cc: pkienzle
>| Subject: str2mat does not accept []
>| 
>| Bug report for Octave 2.0.13 configured for i386-pc-linux-gnu
>| 
>| Description:
>| -----------
>| 
>| I'm trying to build a matrix of strings piecemeal using something like:
>| 	x=[];
>| 	while !feof(file)
>| 	   str = fscanf(file,"%s");
>| 	   str2mat(x,str);
>| 	endwhile
>| but str2mat does not accept [] as an empty string matrix.
>
>I'm not sure that I would call this a bug, since `[]' is an empty
>matrix, not a string.
>
>If you initialize x to be the empty string (x = "" instead of x = []),
>then I think it should work.
>
>jwe
>
>| I don't know what matlab behaviour is in this instance.
>| 
>| Repeat-By:
>| ---------
>| 
>| 
>| Fix:
>| ---
>| 
>| diff -c str2mat.m-2.1.28 str2mat
>| *** str2mat.m-2.1.28	Thu Jun  8 23:18:13 2000
>| --- str2mat.m	Thu Jun  8 23:26:52 2000
>| ***************
>| *** 49,64 ****
>|       s = va_arg ();
>|       if (isstr (s))
>|         [nr(k), nc(k)] = size (s);
>| !     else
>|         error ("str2mat: all arguments must be strings");
>|       endif
>|     endfor
>| - 
>| -   tmp = find (nr == 0);
>| - 
>| -   if (! isempty (tmp))
>| -     nr(tmp) = 1;
>| -   endif
>|   
>|     retval_nr = sum (nr);
>|     retval_nc = max (nc);
>| --- 49,61 ----
>|       s = va_arg ();
>|       if (isstr (s))
>|         [nr(k), nc(k)] = size (s);
>| !       if (nr(k) == 0)
>| ! 	nr(k) = 1;
>| !       endif
>| !     elseif (!isempty (s))
>|         error ("str2mat: all arguments must be strings");
>|       endif
>|     endfor
>|   
>|     retval_nr = sum (nr);
>|     retval_nc = max (nc);
>
>



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