MATLAB Programming

9 Classes and Objects
• subsref — A new portfolio method that enables subscripted reference to
portfolio objects outside of a portfolio method.
• getAccountNumber — a MATLAB function that returns an account number
that consists of the first three letters of the client’s name.
New Portfolio Class Behavior
With the additions and changes made in this example, the portfolio class now
• Includes a field for an account number
• Adds the account number when a portfolio object is saved for the first time
• Automatically updates the older version of portfolio objects when you load
them into the MATLAB workspace
The saveobj Method
MATLAB looks for the portfolio saveobj method whenever the save command
is passed a portfolio object. If @portfolio/saveobj exists, MATLAB passes
the portfolio object to saveobj, which must then return the modified object as
an output argument. The following implementation of saveobj determines if
the object has already been assigned an account number from a previous save
operation. If not, saveobj calls getAccountNumber to obtain the number and
assigns it to the accountNumber field.
function b = saveobj(a)
if isempty(a.accountNumber)
a.accountNumber = getAccountNumber(a);
end
b = a;
The loadobj Method
MATLAB looks for the portfolio loadobj method whenever the load command
detects portfolio objects in the .mat file being loaded. If loadobj exists,
MATLAB passes the portfolio object to loadobj, which must then return
the modified object as an output argument. The output argument is then
loaded into the workspace.
If the input object does not match the current definition as specified by the
constructor function, then MATLAB converts it to a structure containing the
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