Why does my vector turn into a single number in a FOR loop

Im working on a school project where we are supposed to make a vector with 50 elements between 1 and 100, and then make a vector "small" containing the elements under 50 and a vector "big" with the elements over 50. The code ive been trying is:

for x=randi(100,1,50)
  if  x<=50
      small=x;
  else 
      big=x;
  end
end

but when i run the code all the variables becomes single number

Answer 1

[Torsten]

x     = randi(100,1,50);
small = x(x<=50)
big   = x(x>50)

[Stephen23]

+1 the simple MATLAB way.

Answer 2

[madhan ravi]

But it is not efficient use loops , better to use logical indexing instead as mentioned above

   x=randi(100,1,50)
  for i = 1:numel(x) 
    if  x(i)<=50
        small(i)=x(i);
    else 
        big(i)=x(i);
    end
  end

[madhan ravi]

you should put i as an index number in order to prevent overwriting read more about loops and indexing

[madhan ravi]

use nonzeros(small) and nonzero(big) in order to remove zeros from the vectors

[Stian Olsen]

It didn't work completely, the vectors just kept getting bigger when i ran the script several times, however it worked when i changet the code to this

   x=randi(100,1,50);
   small = [];
   big = [];
  for i = 1:numel(x) 
    if  x(i)<=50
        small(numel(small)+1)=x(i);
    else 
        big(numel(big)+1)=x(i);
    end

end

[Stephen23]

@Stian Olsen: note that this a complex and inefficient way to do this task:

https://www.mathworks.com/help/matlab/matlab_prog/preallocating-arrays.html

For much simpler and more efficient code see Torsten's answer.

[madhan ravi]

exactly I agree with Stephen but maybe the OP is requested to stick to for loop since its a project?

[Stephen23]

@madhan ravi: that is possible, but even so it is important to make it clear that this is a bad approach to writing MATLAB code.

[madhan ravi]

yes I completely agree with you @Stephen