Save loop data

I have a for loop, but every iteration overwrites the variable and I have only the final data left.. how can I save data from every loop

for mp=1:100
zsx=somecalc(mp)
end

saves only the last value when mp=100. how do I get the other values?

Answer 1

[Thomas]

Thomas Anthony answered on 8 Mar 2012 at 15:06

This video should help:

http://blogs.mathworks.com/videos/2007/08/20/matlab-basics-video/

You can save the output in a vector or matrix as shown,

Eg:

for i=1:10
y(i)=i+rand;  % use y(i) so that it is written as a vector
end

or you could use:

z=[];
for i=1:10
z=[z i+rand];
end

both should give you similar results..

[Rahul]

thanks, works! did not expect an answer so soon

[Matt Tearle]

Don't forget to preallocate space for the output

% Preallocate space for zsx

zsx = zeros(1,100);

% Loop through elements

for mp = 1:100

% Save mpth element

zsx(mp) = somecalc(mp);

end

Avoid z = [z new_element] in a for loop.

[Austin Hernandez]

I have a similar issue but I need to record the y-values of a line from x=a to x=b.

Each loop, the slope of the line will change so there will be a different set of x and y's for each loop

How can I record the y-values from the function for each loop? The above fix doesn't work if a function is inside of it. This is my code and gives me an error once it trys to record y(i):

function for_test
y = ones(1,1);

for i=1:10
x = 0:1:10;
y(i) = x+rand; % use y(i) so that it is written as a vector
         
end
%I want to be able to access both sets of information when the for loop is over. 
end

[Mahsa Amiri]

Tahnk you Thomas!