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From: Eric on 12 May 2010 13:51
I'm trying to avoid using eval() but am at a loss. My code works fine using eval(), but I'm curious to see if somebody can solve the same problem without it.

I have a class called "Wavefront" with a method called "ToMAT". Let W be an instance of a Wavefront object. I want the behavior of

>>W.ToMAT('filename.mat')

to save the variable W to filename.mat. I want the variable name to be preserved so that

>> load('filename.mat')

creates a variable called W. The only way I have figured out how to do this is with code that looks like the following (I've trimmed out some error handling and other stuff). This is a member function in Wavefront.m.

function [success, filename] = ToMAT(obj, filename)
var_name = inputname(1);
eval(sprintf('%s = obj;', var_name));
save(filename, var_name);

Can somebody solve this problem without using eval?

Thanks,
Eric
From: us on 12 May 2010 14:13
"Eric " <not(a)givingemail.com> wrote in message <hsepq8$1a7$1(a)fred.mathworks.com>...
> I'm trying to avoid using eval() but am at a loss. My code works fine using eval(), but I'm curious to see if somebody can solve the same problem without it.
>
> I have a class called "Wavefront" with a method called "ToMAT". Let W be an instance of a Wavefront object. I want the behavior of
>
> >>W.ToMAT('filename.mat')
>
> to save the variable W to filename.mat. I want the variable name to be preserved so that
>
> >> load('filename.mat')
>
> creates a variable called W. The only way I have figured out how to do this is with code that looks like the following (I've trimmed out some error handling and other stuff). This is a member function in Wavefront.m.
>
> function [success, filename] = ToMAT(obj, filename)
> var_name = inputname(1);
> eval(sprintf('%s = obj;', var_name));
> save(filename, var_name);
>
> Can somebody solve this problem without using eval?
>
> Thanks,
> Eric

one of the many(!) other solutions

function tom(d,fnam)
s.(inputname(1))=d;
save(fnam,'s');
end

us
From: Walter Roberson on 12 May 2010 14:15
Eric wrote:

> I have a class called "Wavefront" with a method called "ToMAT". Let W
> be an instance of a Wavefront object. I want the behavior of
> >>W.ToMAT('filename.mat')
>
> to save the variable W to filename.mat. I want the variable name to be
> preserved so that
>
> >> load('filename.mat')
>
> creates a variable called W. The only way I have figured out how to do
> this is with code that looks like the following (I've trimmed out some
> error handling and other stuff). This is a member function in Wavefront.m.
>
> function [success, filename] = ToMAT(obj, filename)
> var_name = inputname(1);
> eval(sprintf('%s = obj;', var_name));
> save(filename, var_name);
>
> Can somebody solve this problem without using eval?

function [success, filename] = ToMat(obj, filename);
var_name = inputname(1);
SaveStruct.(var_name) = obj;
save(filename, '-STRUCT', SaveStruct);
From: Matt J on 12 May 2010 14:17
"Eric " <not(a)givingemail.com> wrote in message <hsepq8$1a7$1(a)fred.mathworks.com>...
> I'm trying to avoid using eval() but am at a loss. My code works fine using eval(), but I'm curious to see if somebody can solve the same problem without it.
>
> I have a class called "Wavefront" with a method called "ToMAT". Let W be an instance of a Wavefront object. I want the behavior of
>
> >>W.ToMAT('filename.mat')
>
> to save the variable W to filename.mat. I want the variable name to be preserved so that
>
> >> load('filename.mat')
==============

Note: It is dangerous to create variables using load, and therefore questionable why you would want to do this.

The advisable practice is to do

S=load('filename');
myVariable=S.whatever; %whatever is the variable name as stored in the file


> creates a variable called W. The only way I have figured out how to do this is with code that looks like the following (I've trimmed out some error handling and other stuff). This is a member function in Wavefront.m.
>
> function [success, filename] = ToMAT(obj, filename)
> var_name = inputname(1);
> eval(sprintf('%s = obj;', var_name));
> save(filename, var_name);
>
> Can somebody solve this problem without using eval?
==============

The following modification should do it.

function [success, filename] = ToMAT(obj, filename)
var_name = inputname(1);
S.(var_name)=obj;
save(filename, '-struct',S);
From: Walter Roberson on 12 May 2010 14:25
us wrote:

> function tom(d,fnam)
> s.(inputname(1))=d;
> save(fnam,'s');
> end

That would create a .mat file in which the variable name was 's', rather
than being the variable name of the object. Adding the -struct option
does the needed conversion work.
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