I want to compare every matrix element to a constant then calculate a new matrix based on every case

i have a matrix A=[ 1 2 3 4 5 ] and a constant b=3 . and i want to compare each element in that matrix with that constant b and calculate a new matrix based on every case .

if element in A<b then should do A*b

if element in A=>b then should do A+b and i want to calculate a new matrix like this :

C= [ A*b A*b A+b A+b A+b ].

Answer 1

[Voss]

Use logical indexing:

A = [ 1 2 3 4 5 ];
b = 3;

C = zeros(size(A));
C(A < b) = A(A < b)*b;
C(A >= b) = A(A >= b)+b;

disp(C);

     3     6     6     7     8

(Or perhaps more clearly:)

C = zeros(size(A));
idx = A < b; % storing the logical index
C(idx) = A(idx)*b;
C(~idx) = A(~idx)+b;

disp(C);

     3     6     6     7     8

[hamza zoubai]

thank you

[Voss]

You're welcome!