hide empty columns (ajax data)

johan.steurs@staff.telenet.be

with a datatables instance populated by ajax, how can i detect columns without data?
i want to hide those columns ...

the hiding part is not the problem;
table.column(columnIndex).visible(false); // table is a DT instance

how do i determine which column (i.e. columnIndex) does not have data, and especially after the ajax loaded the data?

what i currently have is this:

table.columns().flatten().each( function ( colIdx ) {
    var columnData = table{{loop.index}}.columns(colIdx).data()
    if (columnData.length < 1) {
        table.column(colIdx).visible(false);
    }
});

which does not work, i suspect because the data is not loaded at this point ...
currently i use an object to define the ajax, should i change this to a function and use the callback directly?

i searched this forum and google as well, but couldn't get all this stuff clear in my head, so any help that gets me back on track is appreciated, thanks.

allan

I think your solution is fairly close, but data() will return an array item for each row in the table, which might include empty strings - so the count will always be >0 if you have any rows.

What you could do is use join() to create a string based on the data and then check its length. If 0 then there is no data in the table!

table.columns().flatten().each( function ( colIdx ) {
    var columnData = table{{loop.index}}.columns(colIdx).data().join('');
    if (columnData.length < 1) {
        table.column(colIdx).visible(false);
    }
});

The other option would be to use cells() with a function for a selector for the row selector which would give a list of rows which don't have any data - but I suspect the above might be just as efficient if not more so.

Regards,
Allan

johan.steurs@staff.telenet.be

thanks Allan

for completeness: putting the code in "initComplete": function(settings, json){ .... } helped too ;)

johan.steurs@staff.telenet.be

For others: please note that "table{{loop.index}}" needs to be just "table". Where table is a DataTables instance.

I was careless cleaning the code for this example, the loop index is Python Jinja template code, because i have several DataTables instances in one html