In most of the cases in MATLAB, loops are not essential. As MATLAB is written specifically to work with the vectors and matrices, most operations can be completed and functions can be called with the vectors and matrices. However, the term vectorizing is used in MATLAB for rewriting code by using loops in a traditional programming language to the matrix operations in MATLAB.
In many programming languages, whenever performing an operation on a vector, a for loop is used to loop through the whole vector. For illustration, in MATLAB supposing that there is a vector variable vec:
for i = 1:length(vec)
% do something with vec(i)