Indexing a sub-variable in Matlab base workspace

I do get following when trying to run the code. Error using min. Invalid data type. First argument must be numeric or logical. The concept is that I need to index the y(i).Cost as follow:

[y(i).Cost, y(i).Sol] = CostFunction(particles(i,:);
[ymin, index] = min(y);

Answer 1

[Walter Roberson]

[y(i).Cost, y(i).Sol] = CostFunction(particles(i,:);
[ymin, index] = min([y.Cost]);

Answer 2

[KSSV]

This line:

[ymin, index] = min(y);

Your input to the function min is a structure. min takes an array as input. You need to change the input. Don't input a structure.