changing part of the name of a variable inside a "for" loop

hello everyone!

let's say i have the equation between two variables:

DT10sec= A*T10sec

How can i use a "for" loop to calculate the equation

   DT20sec= A*T20sec
   DT30sec= A*T30sec, 
   DT40sec= A*T40sec,... etc

How can i interfere in just a part of the name of a variable?

[Azzi Abdelmalek]

what do you mean by to calculate equation?

[Matt J]

How did you generate variables T10sec, T20sec, etc... in the first place? Did you have an automated procedure for that? If so, how is what you're trying to do now significantly different?

I assume you know, by the way, that this is a bad thing to do. You could have just had T(1), T(2), T(3), etc... and then simply done DT=A*T.

[vaggelis vaggelakis]

DT and T are matrices. DT10sec is the matrix i want to calculate when T10sec is known. I am asking if it's possible to program a change on the name of the variable, i.e.

for i=10:10:40 DT"i"sec= A* T"i"sec end

Answer 1

[Matt Fig]

Do not program this way! The use of eval is slow, hard to read, difficult to process, works without taking advantage of MATLAB indexing, leads to workspace bloat, locks you into using eval every time you need such variables and prone to bugs. Instead use cell arrays or structures...

It is basic MATLAB not to use eval, in fact it is so common a question that there is a FAQ explaining how to avoid it and alternatives that are standard MATLAB.

Please read this FAQ before you develop a very bad habit.

Answer 2

[Azzi Abdelmalek]

for k=20:10:40
  eval(sprintf('DT%dsec=A*%dsec',k,k))
end

Answer 3

[Wayne King]

You can use eval() for this. For example to to get y1, y2, y3, such that

   y1 = x^1;
   y2 = x^2;

   x = 2;
   for ii = 1:10
     eval(['y' num2str(ii) '=x^' num2str(ii) ';']); 
   end

Now you have variables, y1 through y10 in your workspace. There are good reasons not to do this obviously because you can proliferate the number of variables quite excessively.

Answer 4

[James Cress]

You could do this very easily with a struct.

data = struct;

for k = 1:4

data.(['DT' num2str(k*10) 'sec'])= A*data.(['T' num2str(k*10) 'sec']);

end