MATLAB is a matrix based software that is widely used in engineering. Since the software is matrix based, it is actually a lot faster to do matrix operations rather than looping.
The following is an example of how to create a filter to eliminate all non-positive numbers from an array using the dot operation instead of a for loop.
function y = negative_filter( x ) %========================================================================= % function y = negative_filter( x ) % plugging in a matrix will return only the positive numbers in a vector %========================================================================= %Create a zero matrix same size as the incoming matrix for comparison z = zeros( size(x)); %Create a "filter" matrix that return 1 if the condition is true %It will return 0 if the condition is false filter = (x > z); %This function multply the "filter matrix" with the incoming matrix %elements by elements, note the '.' in front of '*'. This line will set all %number less than 0, or false to the earlier stated condition to 0. y = filter .* x; %This remove all zero terms from the matrix y(y==0) = ;