Extract variables from multiple .mat files

I have ~250 *.mat files in a year with ~25 variables in each file. I need to extract 1 variable from all of the files and create a new *.mat file to validate against other data.

What is the best way to solve this?

Answer 1

[Fangjun Jiang]

My code in this answer could be used for your task too. Take a look to see if you have further questions. Basically, you need to go through a for-loop looping on your ~250 .mat files, taking one variable at a time.

http://www.mathworks.com/matlabcentral/answers/15950-confusion-about-many-many-workspace-variables

[Angela Bowman]

I'm still trying to figure this out. The *.mat files are not in sequential order. I used a for loop to open the files, no problem, but now I am trying to extract data from 3 variables (Lat, Lon and x). Each of these variables has the same matrix size. Lat is in one variable, Lon in another and I need to match those coordinates up to extract the variable x for all 226 files. My result should be 1 variable with a matrix size 226X3. The problem is, the Lat and Long are not listed in the same row, column in each variable.

This has to be possible!

Angela

[Fangjun Jiang]

You'll have to know how to get the variable assuming you are doing it manually one by one (by selecting a particular row and column) first and then write a program to do it automatically. Provide some representative data so it's easy to test it out.

[Angela Bowman]

Lat_coord(222,46);

Lon_coord(364,113);

x_value - let's call it 275 for example - is determined from Lat Lon, but the cell in variable "x_value" is unknown.

Matrix is 407X308, assume all other values NaN.

[Fangjun Jiang]

So how do you pick the value then?

Answer 2

[Walter Roberson]

Please see http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F