How to assign a name for every result in every iteration by using for loop

HI, in the following code:

T = 85; 
Delta_T = 3;
for n = 1:15 
    T = T - Delta_T 
end

How to assign a name for every result in every iteration by using for loop, i want the result for each iteration be like, T1=, T2=, T3=, ... T15=

Answer 1

[Jan]

This is a really bad idea. Hiding an index in the name of a variable is a complicated method, which requires even more complicated methods to access the variables later on. See TUTORIAL: Why and how to avoid Eval.

Prefer to use an index as index:

T0      = 85; 
Delta_T = 3;
T      = zeros(1, 5);
T(1)   = T0;
for n = 2:15 
    T(n) = T(n - 1) - Delta_T; 
end

Now use T(1) instead of T1.

Answer 2

[Walter Roberson]

Compare:

T0 = 85; 
Delta_T = 3;
n = 1;
start = tic;
while toc(start) < 20
    eval(sprintf('T%d = T%d - Delta_T;', n, n-1));
    n = n + 1;
end
variables = who();
size(variables)

ans = 1×2

61625 1

T = 85;
start = tic;
while toc(start) < 20
    T(end+1) = T(end) - Delta_T;
end
size(T)

ans = 1×2

1 44186377

So even when growing an array using indexing is roughly 44186377/61625 which is about 700 times more efficient.

The efffciency for pre-allocating an array and using that array would be much higher still.