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

1 次查看（过去 30 天）
vaggelis vaggelakis
回答： James Cress 2018-6-12
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?
  3 个评论
显示 1更早的评论
Matt J
Matt J 2012-10-6
编辑：Matt J 2012-10-6
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
vaggelis vaggelakis 2012-10-6
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

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Matt Fig
Matt Fig 2012-10-6
编辑：Matt Fig 2012-10-6
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.

更多回答（3 个）

Azzi Abdelmalek
Azzi Abdelmalek 2012-10-6
for k=20:10:40
eval(sprintf('DT%dsec=A*%dsec',k,k))
end
Wayne King
Wayne King 2012-10-6
编辑：Wayne King 2012-10-6
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.
James Cress
James Cress 2018-6-12
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

类别

在 Help Center 和 File Exchange 中查找有关 Programming 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by