How to replace a for loop with a nested if-else condition, to get more velocity

I have a huge vector, and time does matter to my application. I'd like to know how to gain velocity in a code simillar to the shown below (but of course, it is much more complex than this example) :

z = randi(3000);
tic
for i = 1:length(z)
    if z(i) <= 15
        z(i) = [];
        % do something else ...
    end
end
toc

Elapsed time is 0.002744 seconds.

[Rik]

z(z<=15)=[]; will do the same as your loop. How to vectorize code depends strongly on the details of what you want to do.

Answer 1

[Pooja Kumari]

Dear Ana,

I am Pooja Kumari and it is my understanding that you want to replace a for loop with nested if-else condition to improve velocity.

%for the provided code 
z = randi(3000);
tic
for i = 1: length(z)
    if z(i) <= 15
        z(i) = [];
        % Do something else ...
    end
end
toc

You can replace the for loop and if condition given in this code by the following code:

z = randi(3000);
tic
z(z<=15) = []; %updated code 
toc

For more information on tic-toc function, you can follow the provided documentation:

https://in.mathworks.com/help/matlab/ref/toc.html

Sincerely,

Pooja Kumari