Counting Columns in a table

akreider

How can I count how many columns are in a table? Is there a DataTables method for that?

allan

Hi akreider,

There isn't a method specifically for this, but you can access the required property:

[code]
var iColumns = oTable.fnSettings().aoColumns.length;
[/code]
The DataTables settings object contains internal information, and hence is undocumented on this site, but there is a wealth of information in the source code if you need anything more than just the number of columns.

The other option is to query the DOM directly:

[code]
var iColumns = $('#example thead th').length;
[/code]
Regards,
Allan

akreider

I should have thought of that solution. Thanks!

Aaron

akreider

For some reason, Datatables says that this table below has 4 columns (oTable.fnSettings().aoColumns.length;) when it only has 3.

Any ideas?

aoColumns has a fourth column, eg aoColumns[3], that has a blank name and a width of 6 pixels.




Group
St.
ttt

allan

Hi akreider,

Odd - it works okay for me:

[code]
$(document).ready(function() {
var oTable = $('#example').dataTable( );
console.log( oTable.fnSettings().aoColumns.length );
} );
[/code]
Gives a length of 3. Have you initialised your table with bStateSave and altered the number of columns - that is showing a few problems in 1.5.2?

Thanks,
Allan

akreider

I'm unsure what is going on.

This example doesn't work:
http://www.energyjustice.net/map-test/test.html

When I add an extra column, then this example works:
http://www.energyjustice.net/map-test/test2.html

The only difference is an extra in the only column row.


I've tried making tables with 3 or fewer columns, and they don't work.
Could there be a problem with tables that only have three (or fewer) columns?

allan

Hi akreider,

Your pages are both rendering in quirks mode - that in combination with the fact that neither page validates ( http://validator.w3.org/ ) will mean that the browser can do some very weird things. I've tried your table code from the first link in a validating page (strict HTML 4) and it works no problem - so I suspect if you add a doctype to the pages, it will work as expected - you might also need to fix the HTML errors.

Regards,
Allan

akreider

I got it to validate in html strict, but it still won't work.

http://www.energyjustice.net/map-test/test.html

The html validates. The CSS has many errors.

In Firebug, I'm getting "sData is undefined" - line 84 of the jQuery.datatables.min.js file

I guess I'll try removing all the other scripts (except jquery) in case they are causing problems.

allan

Hi akreider,

I totally can't explain that :-). I would imagine it must be an interaction with one of the other script, since I can get your basic HTML table to work for me no problems at all. So yup - I agree - removing the other scripts is the way to go.

Regards,
Allan

akreider

Hmm, this page still has the same trouble. Got rid of most of the scripts (except for my main one). I got the CSS to validate as well.

http://www.energyjustice.net/map-test/test4.html

akreider

Oops! It's in the datatable definition statement. I define it with four columns! So problem solved!

$("#sub-facility").dataTable({"iDisplayLength":20,
"bLengthChange":false,
[{"sType":"html"}, null, null, null]});

allan

Ah ha - that would do it :-). Good one.

Allan