Converting Struct Element Data Type

I am trying to convert to all the field of a nested struct to single precision.

Having noted a similar question on StackOverflow (https://stackoverflow.com/questions/29244516/how-to-convert-datatype-of-all-fields-of-struct-in-matlab-to-double/29244686#29244686), the general solution below works if the fields are only one level, however I have a few nested a nested struct - i.e. struct has elements of variables, arrays and structs which is sometime repeated for multiple levels.

mystruct = cell2struct(cellfun(@single,struct2cell(mystruct),'uni',false),fieldnames(mystruct),1)

Is there a way to list the fields of a struct such that I can apply the method above in a for loop?

My thought is if a have a struct with fields a, b and c, is that I can this method to each of those fields in turn and go to deeper levels if any are structs.

[Rik]

This sounds like you should write a recursive function.

Answer 1

[Dave B]

Hi SRance

To list the fields for a struct, you can use the fieldnames function which you can see in that big line of code. I agree that it might be easier to think about the recursive nature of the problem with a vectorized approach. Here's a demo function which handles the simple cases (but note the comment, you may want to check for other non-struct types).

function somestruct=convert2Single(somestruct)

% Retrieve a list of fields:
fields=fieldnames(somestruct); 

% Loop over fields:
for i = 1:numel(fields)
    if isstruct(somestruct.(fields{i}))
        % If another struct is encountered, recurse.
        somestruct.(fields{i})=convert2Single(somestruct.(fields{i}));
    else
        % Note: Consider other (non-struct) types, if you have a char for 
        % instance it's going to be cast to single...do you want to check 
        % isnumeric? or isdouble? 
        
        % Cast this field to single
        somestruct.(fields{i})=single(somestruct.(fields{i}));
    end
end
end