MATLAB: What does a “~” mean in the following code

Question

A newbie (me) needs to understand a syntax I can't find in the documentation.

if ~isempty(E)
    B=[A
      E'*S]; 
    end;

What does the ~ (tilde) mean or do prior to the isempty(E)?

Answer 1

This is the logical NOT operator, so ~isempty(E) will evaluate to true when E is not empty.