how to find the filed in structure in which a word belongs to?

Hello,

I have a structure that looks like this:

'4412p100.txt' 101x2 table

'FX74-Cl5-140-MOD.dat' 79x2 table

'FX74_CL5_140.dat' 87x2 table

'MultiElementFrontWing.txt' 149x2 table

'NACA4312.dat' 99x2 table

'NACA7412.dat' 100x2 table

'ch10sm.dat' 79x2 table

.

.

.

the user is supposed to select a name from a drop down list, and I want to locate the number of the filed that name belongs to in the structure so that it can be used in further computations

Any ideas how i can achieve that?

I was thinking of representing each name with a number, however the order in the structure will not necessarily be the same as the order in the drop down button.

Also, is there a way to automatically update the drop down button to include anyb new entries saved in the structure?

Thanks!

[Paul]

Are those valid field names for a structure?

[Stephen23]

"Are those valid field names for a structure?

No:

• minus/hyphen characters
• dot characters

"Any ideas how i can achieve that?"

Indexing.

"Also, is there a way to automatically update the drop down button to include anyb new entries saved in the structure?"

Probably, if your code is able to check for when those new entries are added. But it is unclear if you mean "saved" as in "saved in a file" (e.g. a mat file) or just added to the existing structure variable in the workspace. The arrangement of that structure is also unclear: is it scalar or non-scalar, what fieldnames does it have?

[Odysseas Makariou]

This is the code i used to create the structure

(if there is also a more efficient way to do this please let me know)

cd aerofoil_research %where aerofoil_research is a folder in my current folder containing the files i want to include in the structure
k=dir
%checks how many files are in the aerofoil_research folder
num_of_foils=length(k)-2 %the first two elements are '.' and '..'
%creates structure => field = name of file, value = content of file
for i = 1:num_of_foils
    database(i).aerofoil=k(i+2).name
    database(i).coordintaes=readtable(num2str(k(i+2).name))
end
cd ..
%saves created structure as variable in initial folder
clear i k num_of_foils
save aerofoil_database

*where the content of each file to be used in the structure are tables with coordinates

Let me know if this is useful

Thanks!

[Stephen23]

"%the first two elements are '.' and '..'"

No, in general they are not. They might be sometimes (depending on the filesystem and filenames and the DIR match string), but there is absolutely no guarantee of this. For robust code use ISMEMBER or SETDIFF.

Your code would be much more robust if you included a match string (with wildcard) to match the filenames. Then you can avoid fiddling around with the dot-directory names.

Avoid CD in code. It is slow and makes debugging harder.

Why create a new structure when you already have the one returned by DIR?

I recommend using function syntax rather than command syntax:

https://www.mathworks.com/help/matlab/matlab_prog/command-vs-function-syntax.html

P = '.'; % absolute or relative path
D ='aerofoil_research';
S = dir(fullfile(P,D,'*.*'));
for k = 1:numel(S)
    F = fullfile(S(k).folder,S(k).name);
    S(k).data = readtable(F);
end
save('aerofoil_database','S')

[Odysseas Makariou]

okay I will try thank you

Answer 1

[Stephen23]

You can get the index of a specific name using a comma-separated list and STRCMPI (or MATCHES, etc):

For example, where S is your structure:

want = '4412p100.txt'; % the name you want find
idx = strcmpi(want,{S.name});
assert(nnz(idx)==1,'exactly one name must match')
S(idx).data

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

https://www.mathworks.com/help/matlab/matlab_prog/access-multiple-elements-of-a-nonscalar-struct-array.html

[Odysseas Makariou]

thank you!