How can i select variables which has same number at the end

I want to create a code that selects variables with the same number at the end and interpolates them.

where,

there are T_Right_F_224 and time_224 and time is 0:0.01:100

i can make interpolation with interp1(time,T_Right_F_224,time_224)

but,

i want make automation code that select variables with same number at the end

please help.

[Stephen23]

"but these variables are from INCA data which comes from MDF file directly which i didnt meant to name this way....."

You did not tell us the most important information: how did you get those variables into the workspace?

Where these variables are imported would be the best place to fix this bad data design.

Answer 1

[Angelo Yeo]

You can combine string pattern search and eval in order to accomplish what you want. However, in general, it is not recommended to use eval with dynamically named variables. It would be difficult to debug in a near future.

clear;

time_2500= transpose(linspace(0,100, 2500));
T_Right_F_2500 = rand(2500,1);

time_100 = transpose(linspace(0,100, 100));
T_Right_F_100 = rand(100,1);

time = 0:0.01:100;

% Let's see what variables are in workspace
varNames = string(who);

% Let's extract which digits patterns there are 
% The pattern is "time_" plus something.
pat = "time_"+digitsPattern;
idxWithDigits = contains(varNames, pat);
myDigitsPats = unique(extract(varNames(idxWithDigits), pat));
myDigitsPats = extractAfter(myDigitsPats, "_");

for i_pat = 1:length(myDigitsPats)
    % What to evaluate:
    % res_100 = interp1(time_100, T_Right_F_100, time);
    str = "res_"+myDigitsPats(i_pat)+ "= interp1(time_" + myDigitsPats(i_pat)+", T_Right_F_"+myDigitsPats(i_pat)+", time);";
    eval(str)
end

who

Your variables are:

T_Right_F_100   i_pat           myDigitsPats    res_100         str             time_100        varNames        
T_Right_F_2500  idxWithDigits   pat             res_2500        time            time_2500       

Answer 2

[Matt J]

You shouldn't have variables named that way. You should have a cell array T_Right_F{i}, and times{i} and should use indexing to get the corresponding ones,

interp1(time,T_Right_F{224},times{224})

See alos,

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

[Youngjin]

thanks.

but these variables are from INCA data which comes from MDF file directly which i didnt meant to name this way.....

[Matt J]

Then you should undo that damage before proceeding with further work. E.g.,

time_1=[10,20];
time_2=[30,40];
time_3=[50,60];

Times=cell(1,3);
for i=1:numel(Times)
    Times{i}=eval("time_"+i);
end
Times

Times = 1×3 cell array
    {[10 20]}    {[30 40]}    {[50 60]}

[Adam Danz]

@Youngjin how are you accessing the data? Are you loading a mat file that was given to you or are you loading the data from another source?