How to assign a value to a variable in for loop?

Question

azarang asadi 2022-10-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1826633-how-to-assign-a-value-to-a-variable-in-for-loop

评论： Jan 2022-10-15

采纳的回答： Jan

在 MATLAB Online 中打开

Hello all,

I'm getting some input from the user to create the name of a variable as follow:

LocationIMU = string(input('thigh/shank/foot?','s')); %'thigh'
Side = string(input('paretic/non?','s')); %'paretic'
Component = string(input('X/Y/Z/Ox/Oy/Oz?','s')); %'X'
File = string(input('acceleration or angular velocity?','s')); %'acceleration
assignin('base',strcat(LocationIMU,'_' ,File ,'_' ,Component ,'_' ,Side, '_Good'),zeros(101,1));

up to here I get what I want, a variable named thigh_acceleration_X_paretic_Good ( considering the comments as input).

Now I need to creat a for loop and in this for loop I'll be adding new columns to this variable but as this variable can change accordingto input, I don't want to hard code it and need to find a way to add the columns to it. Here's what I am trying to do but as said I don't want it to be hard coded:

for i =1:endLoop
    signal = 1:100;
    thigh_acceleration_X_paretic_Good (:,end+1) = signal;
end

here I hard coded the variable name, how could I do it without writing the variable name and instead having it from inputs?

I hope I could explain what I mean.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Stephen23 2022-10-14

"I hope I could explain what I mean."

We understand what you mean, and we also know that the answer is always the same: do NOT do this.

Meta-data (e.g. location, component, side names) is data, and data belongs in variables (not in variable names). Once you store meta-data in variables, then your code will be neat, simple, and efficient (unlike with what you are trying to do).

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Jan 2022-10-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1826633-how-to-assign-a-value-to-a-variable-in-for-loop#answer_1075173

This is the most frequently asked question from beginners. Professional programmers give the simple and not expected answer: Don't do this! You drill a hole in your own knee.

This is exhaustively explained here: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Do not store important information in the name of variables, but in their values.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2022-10-14

Who imposed the external requirement that you create dynamic variable names?

Jan 2022-10-15

@azarang asadi: As said already, this is the question asked most frequently by beginners. Others and me have dicussed this exhaustively hundreds of times. The results was always the same: You are the programmer and you can write cleaner and better and most of all working code.

Take the chance to learn from the mistakes of others.

请先登录，再进行评论。