Re: textread proeblem

[Philip Nienhuis]

Nidjara wrote
> Hi, 
> I'm reading graphwiz .dot file with octave. This is the sample of the
> file:
> digraph G {
> 1->0  [weight="131932"];
> 2->1  [weight="259178"];
> 3->2  [weight="732180"];
> 4->3  [weight="137337"];
> 5->1  [weight="521430"];
> 6->5  [weight="87498"];
> 7->3  [weight="912756"];
> 8->1  [weight="191335"];
> 9->1  [weight="329365"];
> ..
> 
> I wish to store the first number of every line in vector L1, the second
> number in L2 and the third in L3, ignoring the text. For example, I  would
> like to have 1 in L1(1), 0 in L2(1) and 131932 in L3(1), after loading the
> data. In matlab this code does the trick:
> 
> [L1 L2 L3]= textread('Graph.dot','%u %*2s %u [weight="%d"] %*s',
> 'delimiter',' ;','headerlines',1)
> 
> but in octave I get the following error message
> 
> error: some element undefined in return list.
> 
> Can anyone help me in detecting the problem?

Which Octave version do you use?

In octave-3.8.2 the following just works:

[L1, L2, L3] = textread ('Graph.dot', '%u->%u [weight=" %d"];',
'headerlines', 1)

L1 =

  2
  3
  4
  5
  6
  7
  8
  9

L2 =

  1
  2
  3
  1
  5
  3
  1
  1

L3 =

  259178
  732180
  137337
  521430
   87498
  912756
  191335
  329365


In a debug session I saw that your second format conv. specifier ("%*s2")
was giving problems. Replacing it by a literal solved that. It may be a bug
but at least there's a workaround.

Next up, you do not seem to need ";" as delimiter, and the last format conv.
specifier either ("%*s") is superfluous - it even clobbers up parsing of
your text file in Octave.

Apparently Matlab is more forgiving and that can lead to problems (we quite
often see similar problems, caused by scripts/files with somewhat wonky
syntax accepted by ML but not by Octave).

Philip




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