load multiple files in right order

Hello,

I'm loading multiple mat-files in workspace, the names of files are:

Schweben_Meg_2_2-01_SNR_-030_PLL.mat
Schweben_Meg_2_2-01_SNR_-015_PLL.mat
Schweben_Meg_2_2-01_SNR_000_PLL.mat
Schweben_Meg_2_2-01_SNR_015_PLL.mat
Schweben_Meg_2_2-01_SNR_030_PLL.mat

the answers will be writen to one result files. The problem - MATLAB loads this files in "wrong" order.

First it takes:

Schweben_Meg_2_2-01_SNR_-015_PLL.mat

than

Schweben_Meg_2_2-01_SNR_-030_PLL.mat

than

Schweben_Meg_2_2-01_SNR_000_PLL.mat

.....

I want to get a loading order:

Schweben_Meg_2_2-01_SNR_-030_PLL.mat first

than

Schweben_Meg_2_2-01_SNR_-015_PLL.mat

than

Schweben_Meg_2_2-01_SNR_000_PLL.mat

it is possible to read a data in "right" order without rename of all the files? (I have about 1000x of thoose files)

Thank you!

[Timo Dietz]

I guess you have to isolate the PLL(?) values and sort them separately.

Then re-build the filenames to be loaded.

[Nik Rocky]

Thanks, I try to implement a natsortfiles-function now.

Actually, I made already a workaround tool to resort my results. Small script that turn a first and second row of result. But it's not really nice =)

Answer 1

[Stephen23]

You could download my FEX submission natsortfiles:

https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

and use the regular expression '-?\d{3}' (or similar), e.g.:

D = 'path to the folder where the files are saved';
S = dir(fullfile(D,'Schweben*PLL.mat'));
S = natsortfiles(S,'-?\d{3}'); % alphanumeric sort by filename
... etc

[Nik Rocky]

Hello! Than you, I tried this and get:

sys_var = 

  5×1 struct array with fields:

    name
    folder
    date
    bytes
    isdir
    datenum
 __________________________________________________________
 sys_var.name

ans =

    'Schweben_Meg_2_2-01_SNR_-015_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_-030_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_000_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_015_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_030_PLL.mat' 
_____________________________________________________________
%Implementation with your code
____________________________________________________________
sys_var(1).folder = '/home/nik/workspace/QT/Software_2.0_QT/IO/Schweben_Meg_2_2-01/Schweben_Meg_2_2-01_SNR_F0_F1' % equals your D
_____________________________________________________________
S = dir(fullfile(sys_var(1).folder,'Schweben*PLL.mat')); %second step

S = 

  5×1 struct array with fields:

    name
    folder
    date
    bytes
    isdir
    datenum
__________________________________    
S.name

ans =
    'Schweben_Meg_2_2-01_SNR_-015_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_-030_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_000_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_015_PLL.mat'

    'Schweben_Meg_2_2-01_SNR_030_PLL.mat'
______________________________________
C = natsortfiles({S.name},'-?\d{3}')

C =

  1×5 cell array

  Columns 1 through 3

    {'Schweben_Meg_2_…'}    {'Schweben_Meg_2_…'}    {'Schweben_Meg_2_…'}

  Columns 4 through 5

    {'Schweben_Meg_2_…'}    {'Schweben_Meg_2_…'}
_________________________________________    
C(1)

ans =

  1×1 cell array

    {'Schweben_Meg_2_2-01_SNR_-030_PLL.mat'}
 ....
___________________________________________

Order is right now, but how can I put it back to sys_var variable? Its not more struct, its a cell array!

Thank you!

[Rik]

Use the second output of natsortfiles to sort the original struct.

[Nik Rocky]

Second output? What did you mean? I was looking here https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/47434/versions/7/previews/html/natsortfiles_doc.html but dont find a "second output"

[Rik]

It is right there under the "Output 2: Sort Index" section.

[Nik Rocky]

It sort in wrong order: 000, 015, 030, -015, -030

and I need: -030, -015,000,015,030

_______________________________________

%N = natsortfiles({sys_var.name})

D = sys_var(1).folder
S = dir(fullfile(D,'Schweben*PLL.mat'))
[~,ndx] = natsortfiles({S.name})

ndx =
     3     4     5     1     2

[Stephen23]

As Rik wrote, you can use the second output to sort the structure array returned by dir:

S = dir(fullfile(D,'Schweben*PLL.mat'))
[~,ndx] = natsortfiles({S.name},'-?\d{3}');
S = S(ndx)

This is shown in the Examples documentation, in the section entitled "Example with DIR and a Structure".

Note that you also need to use the second input to natsortfiles (exactly as shown in my answer) as this is what tells natsortfiles to take the negative sign into consideration.

Curiously the link that you gave here is for a very old version of the Examples documentation, the most up-to-date version is always included with the FEX submission itself (you can view it by clicking on the Examples tab):

https://www.mathworks.com/matlabcentral/fileexchange/47434-natural-order-filename-sort

I have no idea why TMW has outdated versions of the documentation still available on its website (and even worse: apparently highly ranked by some prominent internet search engines), but for any FEX submission you should always refer to the help included with the submission itself.

[Nik Rocky]

Thank you Stephen, it works great!

sys_var = dir('**/*.mat'); % looking for directories with mat-files and save to struct
D = sys_var(1).folder; % buffering a path and folder name of files
S = dir(fullfile(D,'*PLL.mat')); % make struct with path, folder name and filename
[~,ndx] = natsortfiles({S.name},'-?\d{3}'); % sorting filenames and saving new index
S = S(ndx); % sorting struct S with new index
sys_var = S; % reinitialize a sys_var variable with new struct

I think is over now!

[Stephen23]

sys_var = dir('**/*.mat');
[~,ndx] = natsortfiles({sys_var.name},'-?\d{3}');
sys_var = sys_var(ndx);

"Thank you Stephen, it works great! "

Please remember to accept my answer if it helped you.

[Nik Rocky]

Great, short and nice!