storing unknown matrices size in a single matrix

Hello everyone,

I have a structure and I use strcmp(data.step(i).comment) to extract the matrices which have the number of student in every class.

example of my issue: I am storing the number of students in every class, Math Class=20 students, Bioology class=18 students and so on. (students number is not constant)

I want to write a code to store all matrices which have the students numbers in a single matrix or vector.

Thanks in advance.

Answer 1

[Ameer Hamza]

If you already have created variable names like that, then you need to concatenate them like this manually

matrix = [math_class, biology, other variables]

and remember to not do such thing again: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[ayman mounir]

Sorry, Maybe I should mintioned that these matrices stored in a structure. So, I use strcmp(data(i).comment command to extract the student number matrices. I think if i am going to use NaN matrix i can solve it but I have alway non mathing dimenstion issue.

[Ameer Hamza]

Can you attach your data in a .mat file? It will help in understanding the problem.

[ayman mounir]

I solved I appreciate your help

Answer 2

[Walter Roberson]

Use an array structure similar to

class_identifier1 student_id1
class_identifier1 student_id2
class_identifier1 student_id3
class_identifier2 student_id4
class_identifier2 student_id2      %that is, student2 is in both courses

so for any one course if you have a list of student identifiers, make it into a column vector, and make a column vector that is all the same, all the same class identifier; with this structure you can vertcat() the matrices to form one large matrix and yet still be able to distinguish which data came from which matrix.