Re: struct weirdness

[Sergei Steshenko]

--- On Thu, 8/23/12, Przemek Klosowski <address@hidden> wrote:

> From: Przemek Klosowski <address@hidden>
> Subject: struct weirdness
> To: "address@hidden" <address@hidden>
> Date: Thursday, August 23, 2012, 7:46 AM
> I was looking at the example from http://wiki.octave.org/Cookbook:
> 
> samples = struct ("patient", {"Bob", "Kevin", "Bob" ,
> "Andrew"},
>                
>    "age",     [ 45 
> ,  52    ,  45   , 
> 23     ],
>                
>    "protein", {"H2B", "CDK2" , "CDK2",
> "Tip60" },
>                
>    "tube"   , [
> 3   ,  5     , 
> 2    ,  18     ]
>                
>    );
> 
> in Octave 3.6.2. I see that samples.patient returns the
> sequence of names, as I'd expect (ans = 'Bob, ans = Kevin,
> etc). However, samples.age returns the 'age' array four
> times. Also, samples(1)
> returns
> 
> scalar structure containing the fields:
>  patient = Bob
>      age =
> 45   52   45   23
>  protein = H2B
>     tube =  3    5   
> 2   18
> 
> rather than what I was hoping for (Bob, 45, H2B, 3).
> 
> This cookbook recipe looked like a neat idea for keeping
> track of complex data but is there a better way using
> struct() for this purpose? or is a newer version of Octave
> required?
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> 

I think you've stumbled upon a number of bugs.

Here is my session (octave-3.6.2) - the 'foo' part is unrelated to your case, 
but it shows what I think is a bug:

"
octave:1> foo.bar = [1 2 3; 4 5 6]
foo =

  scalar structure containing the fields:

    bar =

       1   2   3
       4   5   6


octave:2> size(foo.bar)
ans =

   2   3

octave:3> samples = struct ("patient", {"Bob", "Kevin", "Bob" , "Andrew"},
>                    "age",     [ 45  ,  52    ,  45   ,  23     ],
>                    "protein", {"H2B", "CDK2" , "CDK2", "Tip60" },
>                    "tube"   , [ 3   ,  5     ,  2    ,  18     ]
>                    );
octave:4> samples.tube
ans =

    3    5    2   18

ans =

    3    5    2   18

ans =

    3    5    2   18

ans =

    3    5    2   18

octave:5> size(samples.tube)
error: Invalid call to size.  Correct usage is:

 -- Built-in Function:  size (A)
 -- Built-in Function:  size (A, DIM)


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octave:5> 
".

IMO, since "size(foo.bar)" is accepted above, "size(samples.tube)" (this is 
from your case) should be accepted too, but it is not.

You may check that samples.age is equally problematic.

Regards,
  Sergei.