How to selectively save the names and values of some workspace variables to a CSV file?

Consider the following

a = 3; b=7; c=5; d=9;

save('test.mat')
data = load('test.mat');
toSave = { 'b' ; 'c' };

writecell( horzcat( toSave , <missing code> ) ,'myfile.csv')

what should be the <missing code> in order to have the content of myfile.csv to be

b , 7
c , 5

?

[Rik]

Are b and c guaranteed to be scalar?

[Diaa]

Yes, so far.

Answer 1

[Rik]

This should do the trick. If the variables aren't scalars the results might not be what you want.

a = 3; b=7; c=5; d=9;

save('test.mat')
data = load('test.mat');
toSave = { 'b' ; 'c' };

s=struct;
for n=1:numel(toSave)
    s.(toSave{n})=data.(toSave{n});
end

writecell( horzcat( toSave , struct2cell(s) ) ,'myfile.csv')

[Diaa]

Thanks. Out of curiosity, is there a way to do it without for loop? I mean to extract the values of only the fields I have their names in toSave.

[Rik]

You could also ask load to only retrieve the variables of interest:

s=load('test.mat',toSave{:});

Note that loops have a pretty good performance, as long as you aren't dynamically growing arrays and there isn't a direct function to do it.

[Diaa]

I totally forgot the simple way of selective loading.

Thanks for the hint.

Answer 2

[Diaa]

Thanks to the inspiring answer of @Rik, I found the following solution without the need to use for loop

a = 3; b=7; c=5; d=9;
save('test.mat')
data = load('test.mat');
toSave = { 'b' ; 'c' };
writecell(horzcat(toSave, cellfun( @(C) data.(C),toSave,'UniformOutput',false)),'myfile.csv')

[Rik]

cellfun will only hide the loop. In general it will be slower that a well-written for loop. Just something to be aware of.

[Diaa]

You are right, but I can't resist minimizing the code despite knowing it is not the best practice :)