Last things first. It would be great if you gave your suggestion via the link on the right of the blog. In the meantime, you could make your own struct-like class that would ensure whatever characteristics you want.

As for the performance, what’s happening is that in the original struct, all the fields share the same data. And MATLAB is carefully keeping track of all the references. When you save and then load it, they are each saved as separate arrays so no extra work (reference counting, etc.) needs to happen. Is your test case where the fields share the same data really typical? If not, try the same experiment replacing the repmat array with some random matrices.

–Loren

s=repmat(struct('a',0),5e4,1);
tic;t=[s.a];toc

save s s
clear all
load s
tic;t=[s.a];toc

The [s.a] command takes ~30 seconds on my XP32 system and ~90sec on my XP64 system.

I wrote a simple function in place of the built-in cat:

function out = fcopy(in,fname)
out = repmat(in(1).(fname),size(in));
for i=1:numel(in)
    out(i) = in(i).(fname);
end

Like others above, I also would like to have a homogenous structure array where all structure elements are identical, as in C. It would certainly be more EML-compliant than Matlab’s current heterogenous structure array. I assume we would then be able to access substructures directly. In Erik’s example above, I would hope that [s.px(1)] would work for a homogenous structure. I currently have to copy out fields before I can access elements of them: spx = vertcat(s.px), spx(:,1)

who can help you find the variable names.

varnames = who

inputname will return an empty for temporary variables that are passed (e.g., x(3))

You may be better off constructing an array of the names and passing that in as well.

–Loren

n=nargin;
theStruct = struct;

for ind=1:nargin
theStruct = setfield(theStruct,inputname(ind),varargin{ind});
end
=========================
examples :

a=1;
b=2;
thestruct=createStruct(a,b)
theStruct

theStruct =

a: 1
b: 2
———————
c=3
d=[ 1 2 3]
e= [ 1 2; 3 4]
thestruct=createStruct(a,b,d,e)
thestruct =

a: 1
b: 2
d: [1 2 3]
e: [2×2 double]

Look at the help for the function struct.

–Loren

mystruct =funct(x1,x2,x3)
will be

mystruct.x1
mystruct.x2
mystruct.x3

and if
mystruct =funct(x1,x3)
will be
mystruct.x1
mystruct.x3

how i can create such dynamic struct?

No, you need to know if it’s a cell array or not to use the string appropriately. You are doing it correctly.

–Loren

>> for a = {’b', ‘c’}, a, end
a =
‘b’
a =
‘c’

but then get an error when using ‘a’ as it is actually a cell

>> whos a
Name Size Bytes Class Attributes
a 1×1 62 cell

Ie one has to a{1} to get to the contents.

Is there maybe a better way to traverse a strings list?

Thanks,

Also, when I select multiple blocks, how can I access them?

Thanks