From help-octave-request at bevo dot che dot wisc dot edu Tue Nov 18 09:14:56 2003
Subject: lists and cell arrays ?
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Michael Creel <michael dot creel at uab dot es>
Cc: help-octave at bevo dot che dot wisc dot edu
Date: Tue, 18 Nov 2003 09:14:52 -0600

On 18-Nov-2003, Michael Creel <michael dot creel at uab dot es> wrote:

| Question 1:
| what's the best way to do something like
| 
| 	a = 2;
| 	b = rand(2,1);
| 	c = list(a,b);
| 
| using cell arrays? As far as I can see you need to something like
| 	a = 2;
| 	b = rand(2,1)l
| 	c = cell(2,1);
| 	c(1) = a;
| 	c(2) = b;

Or you can write

  a = ...;
  b = ...;
  c = {a, b};

Soon (hopefully 2.1.52) you will also be able to write

  c = [c1, c2];

to concatentate two cell arrays.
  
| Question 2:
| When one extracts a piece of a cell, the result is a cell, e.g.,
| 
| 	a = rand(2,1);
| 	b = cell(1);
| 	b(1) = a;
| 	a = b(1);  # here, a is now a cell that contains a 2x1 vector.
| 	c = rand(2,1);
| 	a'*c;  # this fails - a is a 1x1 cell, and c is a 2x1 vector

You want to use {} indexing:

  a = b{1};  # here, a is now a 2x1 vector.

BTW, I'm glad to see that people are trying 2.1.51 as the N-d array
code could use some extra testing, but if you should not be surprised
to find some problems.  OTOH, I hope to be fixing most reported
problems fairly quickly and make new snapshots available with those
fixes in a relatively short period of time.

Thanks,

jwe



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