I have tried to make a loop where it displays all the answers in a matrix but it doesn't give me the 21x3 matrix. Am i using wrong commands or am i missing something.

t=0;

for v=[t,sin(t),cos(t)]

if t<21

disp(v)

t=t+1;

end

end

[madhan ravi]

isn't this the same https://www.mathworks.com/matlabcentral/answers/429412-i-have-finished-my-script-but-i-want-to-simplify-it-instead-of-leaving-it-looking-cluttered-i-am-ma ?

[merlin kelly]

I was going through matlab onramp and i am at the loop section so i tried to do the loop on that one. I wasn't getting the answer so i was trying to get a display first but now im trying to plot a graph of it

Answer 1

[Luna]

Hi Merlin,

try this code below:

v = [];
for t = 0:1:20     
    v(t+1,:) = [t,sin(t),cos(t)] ;   
end

[merlin kelly]

Thank you this was very helpful, what happens when v = [ ];, shouldn't i write down v=[t,sin(t),cos(t)] or will that not work

[Luna]

actually I prefer to define v = nan(21,3). Pre-allocation of the size increases the performance, and speed up the for loop.

defining empty ( v = [] ) is something about usage.

For example: if you use your for loop in if-else block, defining empty in the beginning helps you understand whether it goes to if or else block, etc.

You can easily check if isempty(v) that your matrix filled with values or remained empty at end of the process.