How to get corresponding file in another folder?

In one of my folders there are files like "IGN_A.txt", "IGN_B.txt", "IGN_C.txt".........

In another folder there are corresponding files like "sim_IGN_A.txt", "sim_IGN_B.txt", "sim_IGN_C.txt".............

Each of this file contains two columns of same size. How can I create a matrix where two column data from "IGN_A.txt" and two column data from "sim_IGN_A.txt" will be stored side by side. Same thing will be applied to other files.

Answer 1

[Cris LaPierre]

You can include path information in your load command. If you know the path, use that along with the filename to open both files. From there, just load the data from both files, and then create the two matrices combining the data as you wish.

Look into fullfile to help you assemple the full path and filename.

[Mr. 206]

My code is like this

    Flame_speed__Exp_folder = '/home/ali/LFS/test/Test_rig';           
    Flame_speed__Sim_folder = '/home/ali/PostProcess'; 
% To get all the files in that directory and with desired file name pattern.
   Allfiles_Exp = dir(fullfile(Flame_speed__Exp_folder, '*ign*.txt'));
   Allfiles_Sim = dir(fullfile(Flame_speed__Sim_folder, '*sim_ign*.txt'));
 
  
  for k = 1:length(Allfiles_Exp)
    initialFileName = Allfiles_Exp(k).name
    fullFileName = fullfile(Flame_speed__Exp_folder, initialFileName);
    READ=dlmread(fullFileName,'',1,0,"emptyvalue",911911911)
    for kk = 1: length(Allfiles_Sim)
    initialFileName_Sim = Allfiles_Sim(kk).name
    fullFileName_Sim = fullfile(Flame_speed__Sim_folder, initialFileName_Sim);
    READ=dlmread(fullFileName_Sim,'',1,0,"emptyvalue",911911911);
    end 
    end

But the problem is when it enters the second folder( Flame_speed__Sim_folder) it reads and takes all the "sim_IGN_A.txt", "sim_IGN_B.txt", "sim_IGN_C.txt"............. files.

But what i want is read "IGN_A.txt" from first folder (Flame_speed__Exp_folder) than go enter into second folder ( Flame_speed__Sim_folder) and read the corresponding "sim_IGN_A.txt" file and merge their data. Have to do this for rest of the files.

[Cris LaPierre]

Allfiles_Exp will be all files in that folder that match the filter '*ign*.txt'.

Allfiles_Exp_Sim will be all files in that folder that match the filter '*sim_ign*.txt'. There is no connection between the files loaded in either location.

It sounds like instead, Allfiles_Exp_Sim should be the filenames in Allfiles_Exp prepended with 'sim_'. If your naming convention is strictly adhered to, then there is no need to use dir on the Sim folder. Instead, use fullfile with the path to the Sim folder plus the names you get from the Exp folder prepended with 'sim_' to load each file pair.

BTW, the second for loop in your code loads every Sim file for a single Exp file. It is unnecessary with this new approach and can be removed.

Flame_speed__Exp_folder = './ali/LFS/test/Test_rig';           
Flame_speed__Sim_folder = './ali/PostProcess'; 
% To get all the files in that directory and with desired file name pattern.
Allfiles_Exp = dir(fullfile(Flame_speed__Exp_folder, '*ign*.txt'));

for k = 1:length(Allfiles_Exp)
    fullFileName = fullfile(Allfiles_Exp(k).folder, Allfiles_Exp(k).name));
    READ=dlmread(fullFileName,'',1,0,"emptyvalue",911911911);
    
    fullFileName_Sim = fullfile(Flame_speed__Sim_folder, strcat('sim_',Allfiles_Exp(k).name);
    READ=dlmread(fullFileName_Sim,'',1,0,"emptyvalue",911911911);
    ...
end 

Incidentally, your inputs for dlmread are giving me an error. If it is working for you, then disregard. However, the 'emptyvalue' argument is not an option per the documentation.

[Mr. 206]

Thank you so much.

I was doing so because in future there can be files like "sim_IGN_A_Mech01.txt", "sim_IGN_A_Mech02.txt", "sim_IGN_A_Mech03.txt"........... which all correspond to same "IGN_A.txt" file.