Load command don´t work the way I expect!

Hi!

I am trying to use the load command to open a file from a different location and use this script:

[stmfile, stmpath] = uigetfile('*.mat','Pick data file');
Measurefile = fullfile(stmpath, stmfile)

Then I use

disp (Measurefile)

and gets "C:\Matlab\Template\matdata.mat", which is what I expect.

But then I use

load(Measurefile);

and it doesn´t work!

No errors, it simply wont load.

I am quite new to this so please don´t slam me, I just need help.

Thanks in advance!

Ola

Answer 1

[Walter Roberson]

Use

datastruct = load(Measurefile);

Now there will be one field in datastruct for every variable that is stored in the file. For example if there were variables voltage and Power in the file, there would be datastruct.voltage and datastruct.Power fields.

You can cross-check with

size(datastruct)
fieldnames(datastruct)

to see what you loaded.

Note: if you are doing this inside a function, remember that the variables will disappear as soon as the function returns.

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.3F

[Oronnert]

No, the problem is that I don´t see anything at all in the workspace. It loads nothing!

[Walter Roberson]

If you try

datastruct = load(Measurefile);

then what does size(datastruct) and fieldnames(datastruct) report? What does

whos('-file', Measurefile)

report?

[Oronnert]

ans =

     1     1

ans =

    'time'
    'sVcEc_Z_NoxSensUsNoxRaw'
    'sVcEc_Z_NoxSensDsNoxRaw'
    'Scm_VSpd'
    'Spt_GaDPF'
    'Post_NO'
    'Post_NO2'
    'Pre_NO'
    'Pre_NO2'
    'Measurefile'

Name                             Size             Bytes  Class     Attributes

Measurefile                      1x7                 14  char                
Post_NO                      17901x1             143208  double              
Post_NO2                     17901x1             143208  double              
Pre_NO                       17901x1             143208  double              
Pre_NO2                      17901x1             143208  double              
Scm_VSpd                     17901x1             143208  double              
Spt_GaDPF                    17901x1             143208  double              
sVcEc_Z_NoxSensDsNoxRaw      17901x1             143208  double              
sVcEc_Z_NoxSensUsNoxRaw      17901x1             143208  double              
time                         17901x1             143208  double

Is this not what one would expect?

[Walter Roberson]

Then the

 datastruct = load(Measurefile);

did work, and you can go ahead and access the fields you need.

[Oronnert]

But I cannot access the files, and I cannot see them in the workspace.

[Walter Roberson]

datastruct.Post_NO would be the content of the Post_NO variable of that particular Measurefile. Do you see datastruct in the workspace?

One problem you have is that you have a variable named Measurefile saved in your .mat file. When you load() that .mat file without specifying any output, then the Measurefile from the .mat file would overwrite the Measurefile that you had created . That is likely to cause problems. Using the output form of load() and accessing the resulting structure is firmly recommended.

[Oronnert]

Wow! It worked now! accessing it via datastruct.xxx did it! That you very much for your help. I appreciate it a lot. Have a good day!