Searching data inside struct fields ?

I have struct and i need i need to search inside it how can i make this ? let's say i have struct contains fields ID, name and class i need when i get ID from user not accept it if it's found before.

Thanks In advance.

Answer 1

[Walter Roberson]

if ismember(proposed_id, {structname.ID})
  It was a duplicate
 else 
   It did not occur before 
end

If the ID are numeric change from {} to []

[Mohammed kandeel]

It's not working my friend.

lets say i have the following

class.ID=1; class.ID=2; class.ID=3;

and i want to input new ID but user put 2 so i it's not accepted to entered the same ID how can i make it ?

[Mohammed kandeel]

Sorry it's working my friend.

Thanks

[Stephen23]

This code

class.ID=1;
class.ID=2;
class.ID=3;

simply overwrites the field ID with each line, and so defines just one single scalar structure with one field. It is equivalent to:

class.ID=3;

What are you actually trying to achieve? You might need to read about non-scalar structures:

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

[Mohammed kandeel]

It's working my Bro its should be like this it's my fault.

 class(1).ID=1;
 class(2).ID=2;
 class(3).ID=3;