How to assign a value to a variable in for loop?
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azarang asadi on 14 Oct 2022
Commented: Jan on 15 Oct 2022
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;
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.
Stephen23 on 14 Oct 2022
"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).
Jan on 14 Oct 2022
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.
Jan on 15 Oct 2022
@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.
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