DataStore function returns an error

DataStore function returns an error which it shouldn't.

The version of MAtlab is 2018b

Error in line 169 too many input arguments

No problem of my number of the input arguments even the Matlab example does not work.

Line 169 in DataStore.m :

% call the constructor

ds = feval(dsName, location, varargin{:});

[Walter Roberson]

Line 169 in DataStore.m :

DataStore.m is not a file name used in Mathwork's data store; the name used is datastore.m all lower-case.

The feval() call you show is present at roughly that line number, but I have to wonder whether you are using the correct functions.

[Mehdi Shafiei]

I am not using feval(), but datastore.m. The problem sustained when I tried using tabularTextDatastore().

Clarify what you mean by "the correct function".

[Walter Roberson]

You said:

Line 169 in DataStore.m : 

DataStore.m is not the same as datastore.m

[Mehdi Shafiei]

OK! Yes! You mean that!

I correcetd it : datastore.m.

The file DataStore.m that I used was my attempt to replace some lines. Ignore it please and if you may answer my question, plz.

[Mehdi Shafiei]

It is clear that Matlab 2018b has problems running its own Example as I sent it by a screenshot!

[Image Analyst]

Your screenshot shows MATLAB 2012, according to the copyright.

datastore() was introduced in R2014b, according to the bottom my my help documentation for datastore(). Are you sure you're running 2018b and not 2012b? Regardless, try downloading the latest r2020a and trying that.

[per isakson]

I'm sure I run R2018b and I see the same "Copyright 2012".

[Mehdi Shafiei]

@per! do you have the same problem or it is running through?

@Image very strange! I don'rt know what it means. I am sure that I use 2018b I tried on a 2018a on another machine and it works.

It is a very strange problem and I have not modified any function that is in use.

The same functions the same m files and the problem is there for one.

[per isakson]

No problem, see my answer.

Answer 1

[Walter Roberson]

Notice from the header that this is R2018b.

Notice from the output that R2018b does not have a problem with that command.

[Mehdi Shafiei]

It clears up that there shouldn't be a problem with the version.

Good! and thanks!

But where is the problem then?

[Walter Roberson]

You have been modifying MATLAB functions. That makes it difficult for us to guess which modification you made might be interfering with the code.

Answer 2

[per isakson]

I use R2018b

>> version
ans =
    '9.5.0.944444 (R2018b)'    

The example of the help on datastore works as expected in the Live Editor

I cannot guess why it doesn't work on your system.

Proposal:

• Set a breakpoint at line 169 of datastore()
• Run datastore
• At line 169 display the values of the input variables

>> ds = datastore('airlinesmall.csv', 'TreatAsMissing','NA');
169 ds = feval(dsName, location, varargin{:});
K>> dsName, location, varargin{:}
dsName =
    'matlab.io.datastore.TabularTextDatastore'
location =
    'airlinesmall.csv'
ans =
    'TreatAsMissing'
ans =
    'NA'
K>> 

Do you get a different values compared to mine?

[Mehdi Shafiei]

>> version
ans =
    '9.5.0.1298439 (R2018b) Update 7'
K>> dsName, location, varargin{:}

dsName =
    'matlab.io.datastore.TabularTextDatastore'
location =
    'airlinesmall.csv'
ans =
    'TreatAsMissing'

[per isakson]

The string 'NA' is missing, which explains why the error is thrown at line 169. Please, confirm that you didn't miss

ans =
    'NA'

in the copy&paste operation.

[per isakson]

If varargin{:} indeed didn't display 'NA' at line 169, set a breakpoint at line 61, run datastore(), and display location, varargin{:} at line 61. I cannot see any reason why 'NA' would be lost between line 61 and 169.

>> ds = datastore('airlinesmall.csv', 'TreatAsMissing','NA');
61  if isstring(location)
K>> location, varargin{:}
location =
    'airlinesmall.csv'
ans =
    'TreatAsMissing'
ans =
    'NA'
K>> 

Show us a copy from your command window.

[Mehdi Shafiei]

Sorry! Here it is!

And what you think it means?

K>> dsName, location, varargin{:}
dsName =
    'matlab.io.datastore.TabularTextDatastore'
location =
    'airlinesmall.csv'
ans =
    'TreatAsMissing'
ans =
    'NA'

[Mehdi Shafiei]

K>> location, varargin{:}
location =
    'airlinesmall.csv'
ans =
    'TreatAsMissing'
ans =
    'NA'
K>> 

[per isakson]

To make your screen copies more readable

• run format compact
• mark-up relevant text as CODE

"And what you think it means?"

• feval() often throws poor and misleading error messages. The problem is not with the line 169, but somewhere in the method/function that is called by line 169.
• I checked reported bugs at https://se.mathworks.com/support/bugreports without finding anything.
• This might be a question for "Create New Service Request", depending on what type of licence you have.

Otherwise next would be

• Set a breakpoint at line 169 of datastore()
• Run datastore
• At line 169 Step In, (F11)
• and step throw TabularTextDatastore until the error occurs.

See it as a debugging excercise.

[Mehdi Shafiei]

I think I have just said that I have traced the error and got into the method io.datastore.TabularTextDatastore(). Good that another one is on to this.

This should be open for further discussion. Current status is "unsolved."

This is interesting: "

• This might be a question for "Create New Service Request", depending on what type of licence you have."

Appreciated if you further explain it!

BTW I am not a fond buttons nor think the old copy and past affets readability. ;)

[Steven Lord]

Please contact Technical Support using the telephone icon (the Contact Us button) in the upper-right corner of this page.

[Mehdi Shafiei]

Got it!

Cheers

[per isakson]

"[...] I have traced the error and got into the method io.datastore.TabularTextDatastore()." It may well be, but you didn't report what you found.

"nor [...] affets readability" I disagree!

[Mehdi Shafiei]

v.v

;)

[per isakson]

I find it hard to believe that the problem is caused by R2018b proper.

I think the most likely cause is that a function that is called (directly or indirectly) by TabularTextDatastore is shadowed by (has the same name as) a function, which you or someone else has created. Run

dbstop if error
dbstop if caught error

and then

ds = datastore('airlinesmall.csv', 'TreatAsMissing','NA');

The execution may halt at the call of the shadowed function.