How to save the value, a string, of a variable as a variable name of an array ?

Hello,

I have a variable and a double array :

s_fieldnames = 'aaa';
a_nums = [1, 2, 3, 4, 5, 6];

I would like to save this into a mat file. To be clearer, i would like to have a mat file which contains :

aaa = [1, 2, 3, 4, 5, 6];

It means I would like to have the value of s_fieldnames as the name of the double array. So that if i look into my file I will have aaa which contains the double array.

After that I want to use the function save.

save('filename', ...);

Thank you Adrien

Answer 1

[Orion]

Hi,

something like

s_fieldnames = 'aaa';
a_nums = [1, 2, 3, 4, 5, 6];

% create the variable aaa containing the values of a_nums
eval([s_fieldnames '=a_nums;']);

% save it in a mat file
save('filename',s_fieldnames)

[Adrien]

Thank you, it works well.

Answer 2

[Adam]

s_fieldnames = 'aaa';
a_nums = [1, 2, 3, 4, 5, 6];

temp.( s_fieldnames ) = a_nums;

save( 'filename', '-struct', 'temp' );

Try to avoid ever creating variables in your workspace from a string. It isn't a good way to go about things at all even though it is something so many people (myself included) have wanted to do before they know better!

This method allows you to use the inbuilt method for generating structure fieldnames from variables, then save to a mat file with the '-struct' option to get rid of the struct on saving. Judging by the naming of your variable s_fieldnames it was intended to be a structure field name rather than a raw variable anyway!

Note: If s_fieldnames happens to live up to its pluralised name and contain multiple variables you will have to use cellfun or a for loop to do this for each name in the cell array of names.

[Adrien]

Thanks, that was what I was searching for, but didn't found this easy methodic !