Concatenate more than 2 mat files?

Hi, I have 3 mat files which I want to concatenate. The three files may contain similar data variables or different data variables. The values of similar data variables should be concatenated and unique variables should be taken directly. This data should be saved in a new mat file. Can anyone suggest me how to do this. I tried the solution given at link http://www.mathworks.in/matlabcentral/answers/26949. But the solution given at above link is for similar data variables in both the files. Things get messy while concatenating 3 mat files with some data variables unique to only one, or some data variables present in only two mat files. Thus taking common from all the three files does not satisfy the requirements.

1 Comment

An example would be more helpful to understand what you ask. Have you tried cell arrays?

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Answers (2)

Azzi Abdelmalek
Azzi Abdelmalek on 22 May 2013
You can load all your mat-files then concatenate whatever you want
Iain
Iain on 22 May 2013
Edited: Iain on 22 May 2013
You need to load your mat files into variables. File1 = load('filename.mat');
File1 then contains the contents of filename. You need to interrogate that structure to get the list of variable names.
Then, you can make decisions about how to concatenate your files based on the variable names that are common to at least two of your input files.
To then put each of those back into the workspace you'll need to use "eval" to create the right variables in your workspace. - I would suggest you consider using a format other than mat for your input.

3 Comments

Yes, I have loaded the mat files with matfile1 = load([MatFile1Path MatFile1]); in 3 different variables. I am able to get the unique variables from all the three files by extracting the variable names and applying unique to it. But I am not able to concatenate the common variables. I mean, I have the names, I have to identify in which files among all 3 the variable resides and then concatenate it. if it is not a common variable, then just add this variable in the file as it is.
To save the concatenated values back out to file, you will need to make those variables appear in the workspace. You'll need to use something like
eval([variablename ' = [matfile1.' variablename ' matfile2.' variablename ' matfile3.' variablename '];');
But that will throw errors if "variablename" isn't in all of the matfiles, and if there are dimension mismatches...
yes, that's the problem. I could take out the variables that are common in all the 3 mat files, and unique between all the 3 mat files. But, what about the variables that are common to only 2 files? The code works fine if the variables are not common. or if there are only 2 mat files.

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on 22 May 2013

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