I am trying to perform a simple operation FOR loop. I think I am not able to get the indexing right.

%%I am trying to something which seems pretty eady, but I cant get it right.
t1 = [2 7 11 14 16];
t2 = [3 6 9 12 15 17 19];
t3 = [5 8 10 13 14 15 17 19];
%% why does not the following operation work
for i =1:3
    di = 2*ti
end

Answer 1

[Torsten]

%% why does not the following operation work

Because the numbers 1,2 and 3 in t1, t2 and t3 are not indices you can loop over, but part of the three independent variable names t1, t2 and t3.

You can define a cell array with name t with three elements - then its possible to perform numerical operations on the different cell array elements of t:

t{1} = [2 7 11 14 16];
t{2} = [3 6 9 12 15 17 19];
t{3} = [5 8 10 13 14 15 17 19];
for i =1:3
    d{i} = 2*t{i};
end
d

d = 1x3 cell array
    {[4 14 22 28 32]}    {[6 12 18 24 30 34 38]}    {[10 16 20 26 28 30 34 38]}

or shorter

d = cellfun(@(x)2*x,t,'un',0)

d = 1x3 cell array
    {[4 14 22 28 32]}    {[6 12 18 24 30 34 38]}    {[10 16 20 26 28 30 34 38]}

But cell arrays are mostly a bad thing to handle - in order to say what is best in your situation we must know how many such t-arrays exist and what you want to do with them.

[Abhishek K Singh]

Thanks, Torsten!