Saving to .mat without additional struct.

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I have that structure
test =
struct with fields:
F0: 243000
I: [3×3 double]
I_1: [3×3 double]
I_X: 5550000
I_XZ: 33000
%[...]
m: 160000
that i want to save 'as it is'
uisave('test')
I save it as name ('test2'), i load it back and i go this
aircraftdata = load('test2.mat')
aircraftdata =
struct with fields:
test: [1×1 struct]
What i want is a structure like this :
aircraftdata =
struct with fields:
F0: 243000
I: [3×3 double]
I_1: [3×3 double]
I_X: 5550000
I_XZ: 33000
%[...]
m: 160000
The whole point is saving the structure untouched and load it with a new name

Accepted Answer

Steven Lord
Steven Lord on 8 Jul 2022
When you save the struct array, specify the '-struct' option. This will save each of the struct fields separately in the MAT-file. When you call load with an output argument, each of those separate pieces of data from the MAT-file will become fields of the new struct.
S = struct('theAnswer', 42, 'magicMatrix', magic(5), 'nephews', ["Huey", "Dewey", "Louie"])
S = struct with fields:
theAnswer: 42 magicMatrix: [5×5 double] nephews: ["Huey" "Dewey" "Louie"]
cd(tempdir)
name = 'temporaryMatfile.mat';
save(name, '-struct', 'S')
whos('-file', name) % Individual variables
Name Size Bytes Class Attributes magicMatrix 5x5 200 double nephews - 258 string theAnswer 1x1 8 double
data = load(name)
data = struct with fields:
theAnswer: 42 magicMatrix: [5×5 double] nephews: ["Huey" "Dewey" "Louie"]
Compare with:
name2 = 'otherTemporaryMatfile.mat';
save(name2, 'S')
whos('-file', name2) % The struct was stored intact
Name Size Bytes Class Attributes S 1x1 970 struct
data = load(name2)
data = struct with fields:
S: [1×1 struct]
data.S
ans = struct with fields:
theAnswer: 42 magicMatrix: [5×5 double] nephews: ["Huey" "Dewey" "Louie"]
  2 Comments
Gabriel ROUX
Gabriel ROUX on 8 Jul 2022
Edited: Gabriel ROUX on 8 Jul 2022
Thank you very much,
It works fine, but i doesn't suits my needs. I'm working with "uisave()" because it is more user-friendly with AppDesigner. Does uisave allows '-struct' options ? Another issue is that with 'uisave we have no return about what is the filename chosen by the user and what is it's path, so i cannot apply further processing once he's done.
Steven Lord
Steven Lord on 8 Jul 2022
I don't believe uisave offers the '-struct' option. You could try using a different tool, like uiputfile, to select the file to which you want to save. Once you have the file name and path information, use fullfile to construct the fully qualified name and pass name that into save.

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More Answers (2)

Steve Eddins
Steve Eddins on 8 Jul 2022
Try this:
s = load("test2.mat");
aircraftdata = s.test;

Gabriel ROUX
Gabriel ROUX on 8 Jul 2022
I have it https://fr.mathworks.com/matlabcentral/answers/330397-how-can-i-save-some-fields-of-a-struct-using-uisave-function#answer_259211

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