Calculate values only once in the loop

Suppose I have a code running in a loop I have done some operations and I create a matrix in the loop, that matrix has the same size in every iteration. How do i calculate the number of elemens of the matrix only for the first iteration and not for every iteration since i know that it will be the same for every iteration? I want to avoid using ifelse statements.

Answer 1

[KSSV]

Read about function numel. This will give you the number of elements present. Also you can get size of matrix and do product to get the elements.

[D_coder]

I already know that but in my case I want to calculate the number of elements only for the first iteration and avoid calculating the number of elements again and again inside the loop

[KSSV]

for i = 1:N
   if i == 1
      N = numel(A) ;
  end
end

[KALYAN ACHARJYA]

@KSSV Sir, I also looking for the answer, I tried but didn't get the way

%If the condition is true, then only execute the statement

%How to avoid if statement in above code?

N(condition true)=execate the statement

[KSSV]

N = 0 ;   % number of elements 
for i = 1:10
    A = rand(10) ;

      while ~N
          N = numel(A)  ;        
      end
  end

[D_coder]

is there anyother way to calculate without using loops or if else statement. How about N(N==0) = execute the statement

Answer 2

[Amir Xz]

Use "isempty":

I = rand(4,5);r=[]; c=[];
for i=1:10    
  if isempty(r) || isempty(c)
      [r,c]=size(I);
  end
end