MATLAB: Colon operator : problem

colon operatorfaq6.1

Hi, I just found this in ML2009b, that was confusing some calculations I was performing

basically if I create a vector with the colon operator : like this:

idxT = -.5 : 0.02: 1;

I get that p.e. on index 31 I have 0.1: >> idxT(31)

ans = 0.1

BUT if I test it I get this: >> idxT(31)==0.1

ans =

What can I do to solve this problem?

Yes, everyone has this problem. Please read this FAQ

Two approaches: 1. Reshape the matrix at first:

function A = insert_x_into_A(A,x,t)
siz = size(A);
A = reshape(A, [], siz(end));
A(:, t) = x(:);
A = reshape(A, siz);

2. Use a cell as index vector: EDITED: Cleaned up with Bruno's suggestion.

function A = insert_x_into_A(A,x,t)
idx(1:ndims(A) - 1) = {':'};
A(idx{:},t) = x;