MATLAB: How to fill larger array with the values of another array randomized

fill arrayrandom

Hello,
E.g. I got an 'X' array with [1 2 3 4] and want to fill an 'Y' array which is length 8. The restrictions are:
– All values of 'X' array must be in the 'Y' array at least once.
– The values of 'X' are picked random and put in the 'Y' array.
An example of array 'Y' = [1 4 3 1 4 2 1 1].
Is there any function in Matlab which can accomplish this?
Thanks for the help!

Best Answer

I don't think there's anything built-in but it's trivial to write:
function filledarray = randfill(x, n)
    %RANDFILL fill an array of size n with elements of x. 
    %Each element of x is guaranteed to be present at least once
    %prerequisite: n >= numel(x)
    %x: input vector to be shuffled
    %n: size of output vector
    assert(n >= numel(x), 'n must be at least the size of x');
    indices = [1:numel(x), randi([1 numel(x)], 1, n-numel(x))]; %create list of indices 1-numel(x) + random indices
    y = x(indices(randperm(n))); %and shuffle the whole lot.
end
Related Question