(function() {
    'use strict';

    // start with an array of mixed float values
    var dataA = []; // original array
    // generate some values
    _.times(50, function() { 
        var f = _.random(1.1, 9.9);
        dataA.push(d3.round(f, 4));
    });

    // use loDash _.groupBy https://lodash.com/docs#groupBy
    var dataG = _.groupBy(dataA, function(n) {
      return Math.floor(n);
    });

    // create reference array to keys in object
    var keys = _.keys(dataG);

    // visualise organised data
    _.times(keys.length, function(n) { 

        var ul = d3.select('body').append('ul').classed('groups ul-' + n, true);

        ul.selectAll('ul-' + n + ' li')
            .data(dataG[keys[n]])
            .enter().append('li')
            .text(function (d) { return d; });
    });
        

    // show current array
    d3.select('#original-array').text(dataA);

})();