I already have a row matrix, how to change it's dimensions to 5x5 for example?

So this is how it is right now. My matrix A = num(idx) is a row matrix. How can I change it's dimensions to 5x5?

[Matt J]

Please post code in code wells llike below, rather than as screenshots.

num=1:100;
A=num(isprime(num))

A = 1×25

2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Aside from that, your matrix contains only 25 elements, so how would you populate the other 75 elements of a 10x10 matrix?

[Francisco Boudagh]

Right, but lets edit and say 25 numbers. How to make 5x5 matrix of that (instead of row matrix)?

Answer 1

[Walter Roberson]

It looks like you are not being asked to draw the primes between 1 and 100; it looks like you are asked to draw the first 100 primes.

num = 1:600;
idx = isprime(num);
A = num(idx);
if length(A) > 100; A = A(1:100); end
A = reshape(A, 10, 10);
imagesc(A)
colorbar
axis equal tight;

A(end)

ans = 541

However, there is a completely different possibility:

num = reshape(1 : 100, 10, 10);
idx = isprime(num);
imagesc(idx)

[Francisco Boudagh]

Thank you