Generating non-repeating numbers by using a for-loop and break statement

Dear all,

I need to make a function that generates a vector x of n random but unique elements that are smaller or equal to m. If a number is repeated, the function should return an empty vector. If not, the function should just return x. I tried using a for-loop and break statement, but they aren't really working properly. This is my code:

function random=r(m,n)
x=randi(m,1,n); 
for i=1:m
  if sum(x==i)>1 
    break
    disp('[]');
  else
    disp(x);
  end
end
end

Could someone tell me what I'm doing wrong?

Thanks in advance!

Vanessa

[Ive J]

break intuitively means function breaks at that point, so it won't continue to lines after. You need to move disp before break.

[Vanessa Huijgevoort]

Ah thank you that worked!

[dpb]

Above answers why the function doesn't display the empty return case; you could remove the need for a loop entirely

function random=r(m,n)
  x=randi(m,1,n); 
  if numel(unique(x)<m)
    disp('[]');
  else
    disp(x);
  end
end

Answer 1

[dpb]

The function doesn't return anything, though...either your original nor mine. I didn't catch that before. If the idea is to return the generated vector if it is unique or an empty vector [] if there is a duplication, then need

function x=r(m,n)
  x=randi(m,1,n); 
  if numel(unique(x)<m)
    x=[];
  end
end

Above I've also presumed it really is intended to just echo the result to the command line but to return the requested data instead.