From help-request at octave dot org  Tue Nov  9 16:59:42 2004
Subject: Re: What is wrong here?
From: Geraint Paul Bevan <gbevan at eng dot gla dot ac dot uk>
To: Vic Norton <vic at norton dot name>
cc: help at octave dot org
Date: Tue, 9 Nov 2004 21:41:07 +0000 (GMT)

On Tue, 9 Nov 2004, Vic Norton wrote:

> octave> for i = invIndices(1:3)
> >  printf ("%3u: %s\n", i, dates(i, :));
> >  endfor
> 234: warning: implicit conversion from matrix to string
> ???
> 218: 102545---MSSaeeypp---222000000000
>
> What is wrong with using the column vector invIndices(1:3) as an
> index set? Why does it foul up the date array?

The problem is that the entire column is assigned to the loop variable on
the first pass:

# column vector
octave> a = [1;2;3];
octave> for i = a; disp ( "i: "); disp ( i ); endfor
i:
  1
  2
  3

This is consistent with what you get when you loop over a matrix

octave> a = [1,2,3;4,5,6;7,8,9];
octave> for i = a; disp ( "i: "); disp ( i ); endfor
i:
  1
  4
  7
i:
  2
  5
  8
i:
  3
  6
  9

This means, however, that the entire array is being passed to the printf
function - hence the error message. Therefore you will need to transpose
your invIndices vector so that it is a row vector when looped over.

-- 
Geraint Bevan
http://homepage.ntlworld.com/geraint.bevan



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