How to determine if a data table is already opened?

[#1]

This is how I used to do it before JMP 8:

tableIsOpen = Function( {tname},
	{dt, rv = 0},
	Try(
		dt = Data Table( tname );
		rv = 1;
	);
	rv;
);

This does not work in JMP verison 8 because DataTable function will open a file dialog if the table is not opened already. User can always press "cancel" but it's annoying.

Thanks for any help.
Tommy

[#2]

You can loop through all the open tables by passing a number to Data Table() and compare names.

tableIsOpen = Function( {tname},
	{rv = 0, i},
	For( i = 1, i < N Table() + 1 & rv == 0, i++,
		If( Lowercase( Data Table( i ) << Get Name ) == Lowercase( tname ),
			rv = 1
		)
	);
	rv;
);

edit: with a "<=" option

tableIsOpen = Function( {tname},
	{rv = 0, i},
	For( i = 1, i <= N Table() & rv == 0, i++,
		If( Lowercase( Data Table( i ) << Get Name ) == Lowercase( tname ),
			rv = 1
		)
	);
	rv;
);

(The forum software really doesn't like less than or equal, which is why I use plain less than and added 1.)

[#3]

Thanks for the code. I'm trying it out now.
I wish there's a more straight forward way of checking for opened data file.

[#4]

Came across this thread looking for something similar for closing lingering open data tables at the beginning of my script while testing code, instead of counting them. Used a combo of the code posted here and in another thread. Thought I'd post in case it's useful for anyone coming across this thread:

// list of table names that I want to make sure are closed before running the script
tname = { "TABLE1", "TABLE2", "TABLE3", "TABLE4" };

// loop to see if open tables match the name in the list above, then close them
// need to restart the i counter to i = 0 because it seems closing a table changes the 'i' number associated with the table
For( i = 1, i <= N Table(), i++,

	If( N Rows (Loc( tname, Data Table(i) << Get Name ) ) > 0, 
		Close(Data Table(i), no save);
		i = 0;
	)
);

[#5]

I would simplify the closing by using the Try() function

Names Default To Here( 1 );

tname = {"TABLE1", "TABLE2", "TABLE3", "TABLE4"};

For Each( {dt}, tname,
	Try( Close( data table( dt ), nosave ) )
);