Specific conditions for array elements

Hello! Let's say that i have an array 5x5 filled with numbers from 1 to 20

A=randi(20,5);

How can i compute a new array B of the same size as the A with three conditions:

1. If the element of the array A is smaller than 10, B=9^2

2. If the element of the array A is equal to 10, B=0

3. If the element of the array A is higher than 10, B=20^0.5

Thank you,

Alex

Answer 1

[Awais Saeed]

Fairly simple

clc;clear;close

A=randi(20,5);
B = A;
% get indices
B1 = find(B == 10);
B2 = find(B > 10);
B3 = find(B < 10);

% change values at those indices
B(B1) = 0;
B(B2) = 20^0.5;
B(B3) = 9^2;

[Alexander Nee]

Dear Awais Saeed,

Many thanks for your clear explanation! Can you also help me with that. Now, we have the array B computed the above. Along with that, we have random array C.

C=rand(5);

Can i change the elements of the array C to zero, where the elements of the array B is equal to 81?

[Awais Saeed]

You are welcome.

C = rand(5)
% get indices where B = 81
C1 = find(B == 81);
% change values at those indices to zero
C(C1) = 0

[Alexander Nee]

Thank you! You greatly helped me!

Answer 2

[Simon Chan]

You may simply combine them together as follows:

B = (A>10)*(9^2)+(A==10)*0+(A<10)*(20^0.5);

[Alexander Nee]

Dear Simon Chan,

Thanks for your response!