Create structure with field names from an array

Question

Below I have a snippet of code that I am using to create a structure with field names that are defined in the array 'field_names'. This seems like a very clunky way of creating the structure.

Is there a better way that I can do this in one line? Perhaps there is some syntax trick to help me avoid the for loop?

%array of names to create field names from
field_names = ['num1', 'num2', 'num3', 'etc'];
data = struct()
for i = 1:length(field_names)
    data.field_names(i) = rand() %some random value, doesn't matter for now
end

score 3 · Accepted Answer · answered Sep 19 '16 at 17:51

So first of all, the way you've written it won't work since field_names should be a cell array, and struct dynamic field referencing requires parentheses:

data.(field_names{i}) = rand();

You can use cell2struct to construct the struct using those fieldnames and the desired values.

field_names = {'num1', 'num2', 'num3'};
values = num2cell(rand(size(field_names)));

S = cell2struct(values(:), field_names(:))

%    num1: 0.2277
%    num2: 0.4357
%    num3: 0.3111

You can also create all of the field and values when calling struct directly:

S = struct('num1', rand(), 'num2', rand(), 'num3', rand());

Create structure with field names from an array

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