Reference to a variable

hi, I am loading a huge amount of data into a database. The database is dynamic and sometimes will hold 50 separate entities and sometime less. Each entity than has a list of up to 10,000 separate variables, each of which is a table of values. I need a way to hold pointers (or references) to the variables to ease later scanning of the database of only particular data. I don't know in advance the number of items in each entity or the number of entities. I was thinking using whos and/or fieldnames to scan the database and get a complete list of all the variable names. But once I have the reference (for example as a string of the var name) how to I access that variable's value? For example if there is a variable called David and its value is 7, and if I have a string 'David', how can I get the value from the string?

Answer 1

[Jan]

What exactly is "a database"? Do you mean a database?

The last sentence of your question sounds like you want to use dynamic fieldnames:

Data.Field1 = rand(3)
Name = 'Field1';
Index = {2, 3}
disp(Data.(Name)(Index{:}))

But the initial part of the question let me assume, that you better use a database program.

[Gil Levi]

I would use a database but the computations are extremely complex and can't be done in a practical manner without MATLAB (or similar). So I prefer implementing it in MATLAB. When I mentioned database I was thinking about a variable that will hold all the data. When I load such a variable later and I want to access only specific fields within the data and be able to scan only through these fields (i.e. run a for loop only on the specific data that I need) and I have a string name of the field which is a small part of the entire variable. ........... running your example I think you answered my question. I can use fieldnames to learn all available fields in the variable (my database) and then use the strings with "your" parenthesis method to access them later. Thanks a lot.