Concatenation of multiple matfile into one matfile

Hi Hello everyone, i have multiples mat files and i would like to concatenate them (merge vertically) in one matfile, all my matfiles have values only, (9 columns and several lines,), the output should be 1 file with 9 columns and all the lines from the previous multiples matfiles

[Matt J]

Do all the files contain only a single variable? Is the name of the variable the same in all the files? How many files and what determines the order of the concatenation?

[MEHDI HAMIDI]

my files contains 9 columns and and several lines and it's only numbers e.g line 1 : 1 2 3 4 6 7 8 9,

line 2 : 1 9 8 8 2 3 7 8 9, i have 75 files the order doesnt matter, thank you sir

Answer 1

[Stephen23]

Assuming that each .mat file contains only one variable of unknown name:

P = 'absolute or relative path to where the files are saved';
S = dir(fullfile(P,'*.mat'));
for k = 1:numel(S)
    F = fullfile(P,S(k).name);
    C = struct2cell(load(F));
    S(k).data = C{1};
end
M = vertcat(S.data);
save('newfile.mat','M')

[MEHDI HAMIDI]

Thank you sir i really appreciate your help it did work, but i would like to know something, on the workspace i see all the variables used, C,F,K,M,P,S when i load the newfile.mat, only the variable M contains exaclty what i want, im gonna use this file for some otherwork and i wonder if i load it it will cause a problem due to the other variables (C,F ...) Thank you for your help

[Stephen23]

@MEHDI HAMIDI: the code I gave you only saves matrix M, because that is contains your concatenated data. You do not need the other variables.

[MEHDI HAMIDI]

Nevermind, it actually works thanks a lot

Answer 2

[Benjamin Thompson]

MAT files contain a list of variables with your data. Please post a sample MAT file for the Community to see if you have further questions. You could use the structure return syntax from the load function:

S = load(FILENAME) loads the variables from a MAT-file into a structure

array, or data from an ASCII file into a double-precision array.

Specify FILENAME as a character vector or a string scalar. For example,

specify FILENAME as 'myFile.mat' or "myFile.mat".

S1 = load(FILENAME1);

S2 = load(FILENAME2);

Then you could combine the data in structures S1, S2, etc into a final structure or some other form.

[MEHDI HAMIDI]

here an example sir

[Benjamin Thompson]

Ok, so you load it:

>> S1 = load('Snap1_0_360.mat')

S1 =

struct with fields:

OmniPDP: [10×9 double]

You can copy S1 to a new Stotal that might receive the contents of other files:

>> Stotal = S1

Stotal =

struct with fields:

OmniPDP: [10×9 double]

And this example you could easily replace the second copy of S1 with some of your other files like S2. Here I just show how to create a combined OmniPDP member in Stotal using S1 twice.

>> Stotal.OmniPDP = [S1.OmniPDP; S1.OmniPDP];

>> Stotal

Stotal =

struct with fields:

OmniPDP: [20×9 double]

[MEHDI HAMIDI]

Thanks you sir