Can I extract unique values from a returned data object?

westtown

My application has a Select, based on the unique values of a data column.
I am extending my application and will now use a column that returns a list of objects like this:

locations: [
{
location1_id: { id: 59, location_name: 'London' }
location2_id: { id: 28, location_name: 'Liverpool' }
}

This list will always hold at least a single record in the object.
It may hold two or more.

Is there a way to select the unique values from all the objects, in order that the Select would find all records where the first or second location = Liverpool?

Thanks, Tony

allan

Hi Tony,

I'm not clear on how this will be used with DataTables. Do you want to show that information in a DataTable? What is the Select you mention. Is that a <select> element inside Editor?

Allan

westtown

Hi Allan,

I have a Column Select, but it's located above the table - code shown below. This Select is working fine, on a column with a single data item (which may or may not exist).
However, I want to upgrade this select, so that it handles data which is an array of json objects.

The current data looks like this:

 _clubs: {
      id: 202,
      created_at: 1618941193000,
      ClubName: 'Hull City',
      countries_id: 0
    },

This is the DT API that builds the select for the current data.

 this.api()
    .columns(3)
    .every(function () {
        var column = this;
        var select = $('<select class="form-select"><option value="">Select Club</option></select>')
            
            //  .appendTo($(column.footer()).empty())
           .appendTo($("#selectClub"))
            .on('change', function () {
                var val = $.fn.dataTable.util.escapeRegex($(this).val());

                column.search(val ? '^' + val + '$' : '', true, false).draw();
            });

        column
            .data()
            .unique()
            .sort()
            .each(function (d, j) {
                select.append('<option value="' + d + '">' + d + '</option>');
            });
    });

The data coming in is now in a JSON array of objects, because the user could have zero, one or many clubs. It looks like this:

clubs: Array(2) [ {…}, {…} ]
​​​​
0: Object { clubs_id: 202, _clubs: {…} }
​​​​​
    _clubs: Object { id: 202, ClubName: "Hull City", countries_id: 0 }
    
    
1: Object { clubs_id: 200, _clubs: {…} }
​​​​​
    _clubs: Object { id: 200, ClubName: "Leeds United", countries_id: 0 }
​​​​​​

My question was: how to enhance the current code, so as to the unique values from this column, into a select.

Many thanks,
Tony

kthorngren

Use column().index(), in an if statement, to check for the column that you want to process the select list differently. For example:

    // Process column 0 differently
    if ( column.index() === 0 ) {
        // Code to extract data from object
    } else {
      column.data().unique().sort().each(function(d, j) {
        select.append('<option value="' + d + '">' + d + '</option>');
      });
    }

You might need to use Orthogonal data to set the filter value to match what you place in the select list.

If you need help with this then please build a simple example that has a sample of your data and provide specific details of how you want the select list built.
https://datatables.net/manual/tech-notes/10#How-to-provide-a-test-case

Kevin