How can I create a method which takes an excel file as an argument in a constructor?

Basically, I'm trying to construct a method that allows users to input a data file. It can be excel or ascii, and the method reads it as a matrix which can then be tested on.

Here is some of the rudimentary code I've modified from the tutorial:

classdef BankAccount < handle
  properties (Hidden)
      AccountStatus = 'open';
  end

    properties (SetAccess = private)
        VEC
        AccountBalance = 0;
    end

    events
        InsufficientFunds
    end

    methods
        function BA = BankAccount(filename, InitialBalance)
            BA.VEC = xlsread(filename);
            BA.AccountBalance = InitialBalance;

then I try: BankAccount('sample.xlsx',55)

I'm getting an error: No public field VEC exists for class BankAccount.

Error in BankAccount (line 20) BA.VEC = xlsread(filename);

[Cedric]

Which version of MATLAB are you using? After adding all missing end, your code is working on mine (R2011b).

[Jordan Ledvina]

hey Cedric, thanks for the prompt reply. I'm using R2012b.

Did you run it with an input like : BankAccount('sample.xlsx',55)

where sample.xlsx is a file in your matlab folder?

I guess I'm not sure why VEC needs to be a public field? What does that error typically signify? Even when I try to make it public, matlab doesn't like it.

Answer 1

[Cedric]

My guess is that it has nothing to do with the fact that you want to read an xls file.

If you really have the code that you gave above, with 3 additional end at the end and nothing else like setters/getters or overloads of subsasgn/subsref, i.e.:

 classdef BankAccount < handle
    properties (Hidden)
       AccountStatus = 'open';
    end

    properties (SetAccess = private)
       VEC
       AccountBalance = 0;
    end

    events
       InsufficientFunds
    end

    methods
       function BA = BankAccount(filename, InitialBalance)
          BA.VEC = xlsread(filename);
          BA.AccountBalance = InitialBalance;
       end
    end
 end

then the error..

• Could be related to something new in R2012a that I will discover in less than 2 weeks according to my license manager ;-)
• Could come from a upper/lowercase mismatch between the declaration of properties and the constructor (like BA.VEc=.., that I don't observe in what you pasted actually).
• I am unsure whether the editor would allow that, but could you have some sort of invisible special character that came during the copy-paste that you probably made from the PDF manual about OOP in MATLAB?

You could perform a few checks actually. Try replacing

 BA.VEC = xlsread(filename);

with

 BA.VEC = [] ;

so you eliminate anything related to xls stuff. If it still generates an error on VEC, try commenting the line and see it is specific to VEC or if it happens as well with AccountBalance.

You could also comment out the events block and avoid subclassing handle, to see if the issue comes from some conflict with handle methods/properties..

 classdef BankAccount %< handle
    ...
    %events
    %   InsufficientFunds
    %end
    ...

Cheers,

Cedric

Answer 2

[Jordan Ledvina]

Hey Cedric,

It works. I commented out handle then I restored it and it worked just fine.

Not really sure what the problem was but I thank you all the same for your expedient and thorough answer.

[Cedric]

Great! I already had issues with '<' in other contexts after cut and paste from PDFs. If you deleted < handle and rewrote it afterwards it might be something similar that happened.. I guess you'll discover that after your next cut and paste ;-)

Cheers,

Cedric