Convert struct to double type in Matlab

Question

Glcm (feature extraction method) give me an output in \'struct\' type, while i need the output in \'double\' type. I need a \'double\' type as the input variable for the nex

Answer 1

First of all, rather than first converting to a cell and then to a matrix, you can convert directly from a struct to a double using struct2array.

fetrain = struct2array(gl);

That aside, there is no difference between a "complex double" and a double. They are both of type double.

class(1i)
% double

You can use real to get the real component of the complex number or abs if you need the magnitude of it.

real(1+1i)
%   1

abs(1+1i)
%   1.4142

In your case this would be:

fetrain_real = real(fetrain);
fetrain_mag = abs(fetrain);

Update

By default struct2array concatenates the data horizontally. If you want your data to be a matrix that is nFields x nData, then you could do something like the following:

fetrain = struct2array(gl);

% Reshape to be nFields x nData
fetrain = permute(reshape(fetrain, [], numel(fieldnames(gl)), numel(gl)), [2 1 3]);