How can i edit a .mat file

I have a .mat file name.mat. It contains information such as and when I open it the import wizard opens. now say the data in the import wizard is as follows:

|var_name | Ixx | Iyy | Izz

A            1     2    3

B            4     5    6

C            7     8    9

Now say I wanted to go in and update the numbers to 2-10 -- how do I do this? Or, how can I create a .mat file?

I tried using the import wizard and creating my own, but when I do, it doesn't include having the variable names in the same table because they're letters and not numbers.

Thanks

Answer 1

[Image Analyst]

You have to read it all in:

storedStructure = load('name.mat');
A = storedStructure.A;
B = storedStructure.B;
C = storedStructure.C;

Then change things:

A = [1 2 3];
B = rand(1,3);
C = randi(100, 3);

Then save it back:

save('name.mat', 'A', 'B', 'C');

[Arthur Vieira]

If I have variables in my workspace that I don't want to loose (i.e. can't load the .mat in), how can I update what's in the .mat file? Including deleting a variable within a .mat file? I could load them with:

var = load('myData.mat');

But that makes 'var' a structure. And you can't save variables within structures for some reason. I'm confused on how you're meant to use .mat files.

[Steven Lord]

After you load the variables from the MAT-file into a struct array and modify the fields of that struct, call save with the '-struct' option and the name of the struct array.

cd(tempdir)
v = struct('x', 1:10, 'y', @sin, 'z', "abracadabra");
save('mymatfile.mat', '-struct', 'v')
whos -file mymatfile.mat

  Name      Size            Bytes  Class              Attributes

  x         1x10               80  double                       
  y         1x1                32  function_handle              
  z          -                158  string                       

The MAT-file does not contain the struct v but contains three variables, one for each field in v.

Answer 2

[Azzi Abdelmalek]

a=10; v=magic(4)
save filename a v

To load your file

 load filename

[Kim Nguyen]

this doesnt solve the problem of having letters, also i already have a data file, like an excel that i would like to load into matlab which is part of the problem. it seperates the character string from the number and therefore does not do what i need

[Azzi Abdelmalek]

fid=fopen('file1.txt')
x=textscan(fid,'%s %f %f %f')
fclose(fid)
out=cell2mat(x(2:end))

% to get the characters

d=x(1)
lett=d{:}