MATLAB: Need to find numbers divisible by 2 through 100

Question

hi i want to count the values in given vector/matrix that are divisible by 2-100.

y has few thousand random digits.

here is the code that i stitched but its giving me error. i want to create a vector divby which holds count of all values divisible by specific number and increment its corresponding value in value in the index .. say count of values divisible by 7 are held in divby(y) .. and after each iteration if a value is divisble by 7 divby[7] should increment by 1.

y=[3 3 43 45 2 2 34 5 ] % (it has a lot of such random values (most are 6 figure values) 
divby=[];
ndivby=[];
for k=2:99
      for i=1:length(y)
          if(mod(y(i),k)==0)
              divby(k)=divby(k)+1;
          else  
              ndivby(k)=ndivby(k)+1;
          end
      end
  end

i am getting below error Index exceeds matrix dimensions.

Error in all25k3rd (line 60) divby(k)=divby(k)+1;

Please help

Answer 1

Preallocate your arrays like this instead of as empty arrays:

divby=zeros(1,99);
ndivby=zeros(1,99);