MATLAB: Indexing structured arrays

arrayindexingstructure

I have a two structures that have identical fields, but different lengths. I want to append part of one structure to the other. This works for a single element, but I want to vectorize it. I have tried

Struct1(i:i+n).parm1 = Struct2(k:k+n).parm1;

where i is the length of Struct1 and k and k+n are integers that lie within Struct2 length. However, I get the error "Insufficient outputs from right hand side to satisfy comma separated list expansion on left hand side. Missing [] are the most likely cause."

How do I make this kind of assignment without writing a for loop?

Best Answer

Have you tried

    new_struct = cat( Struct1(i:i+n), Struct2(k:k+n) );

Are the fields in the same order? Try this

    [ Struct1(i:i+n).parm1 ] = [ Struct2(k:k+n).parm1 ];

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MATLAB: Initialise a table which contains a structure and a sub-structure

Subscripted assignment between dissimilar structures

This is because you're trying to change one element of a structure array to a different structure. If you changed the whole structure array instead you wouldn't get the error. Thus instead of your k loop:

initstruct = struct(...  %your structure initialisation code that I'm not copying)
pdat(pti).(varray{i}).raw = repmat(initstruct, height(pdat(pti).(varray{i}), 1);

However, rather than preallocating the table with a default structure and then replacing it later on by a different structure, I'd just create the table directly with the right structure. That involves creating default arrays for all columns instead of using the 'Size', sz, 'VariableTypes', varTypes syntax, but I think it's cleaner:

initraw = struct(...  %your structure initialisation code that I'm not copying)
initpeak = struct(... %some other structure)
pdat(pti).(varray{i}) = table(false(maxsess, 1), ...
                              false(maxsess, 1), ...
                              zeros(maxsess, 1, 'int8'), ...
                              repmat(initraw, maxsess, 1), ...
                              repmat(initpeak, maxsess, 1), ...
                              'VariableNames', {'isAC',    'isCvemp', 'iteration', 'raw',    'peaks'});

MATLAB: Removing structure field if

fn1 = fieldnames(Struct1);
fn2 = fieldnames(Struct2);
tf = ismember(fn2, fn1);
NewStruct = struct();
for K = 1 : length(tf)
  if tf(K); NewStruct.(fn2{K}) = Struct2.(fn2{K}); end
end

I expect that is also a vectorized formulation that uses struct2cell()

Best Answer

Related Solutions

MATLAB: Initialise a table which contains a structure and a sub-structure

MATLAB: Removing structure field if

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