how to set value in jquery by index

i have data in select option

$.ajax({
    url: "<?php echo site_url('method/....'); ?>",
    method: "POST",
    data: {
        id: id
    },
    async: false,
    dataType: 'json',
    success: function(data) {
        var $html = $('.appendBarangs[indexOf=' + n + ']').html('<option value="">pilih</option>')
        for (y in data)
            $html.append('<option value = ' + data[y].id_barang + ' name=' + data[y].barang + '>' + data[y].barang + '</option>');

        $('select').on('change', function() { //here i make a function take attribute name
            var dapet = this.options[this.selectedIndex].label;
            console.log('dapet', dapet)
            $('.attributItem[indexOf=' + n + ']').val(dapet);
        });
    },
})

here I take the name attribute from the results of the ajax response, then I throw it into the input form based on index

this my form input , but not work

'<input class="form-control attributItem" name="item[]" type="text" indexOf='+n+ '/>'+

if not using indexOf , the name attribute is successfully thrown into the input form.

how ?