How to push data into highchart with just one decimal place?

Question

I´m trying to make sinus and cosinus graphs. There are pushed data like this:

data: (function exp() {
                var data1 = [],
                    //i = 0,
                    x = 0,
                    y = 0;

                for (i = -10; i <= 10; i = i + 0.1) {
                    //x = i.toFixed(4);
                    x = i;
                    y = Math.sin(i);
                    data1.push({
                        //x: Math.round(i * 10000)/10000,
                        x: x,
                        y: y,
                    });
                    if ((y.toFixed(4) == 0) || (y.toFixed(4) == -0)) {
                        //var x = Math.sin(Math.round(i * 10000)/10000);
                        //var y = Math.round(Math.sin(i) * 10000)/10000;
                        addtext(x, y);
                    }
                }
                return data1;
        })()
    },

So there should be x values: -10; -9.9; -9.8, -9.7 and so on...But if you look at graph(http://jsfiddle.net/K5Zhr/4/), there are x values: -10; -9.9; -9.8, and then there is -9.700000000000001 and all next x values are screwed up in same way.

I have tried to use methods .toFixed and .toPrecision, but they (for example) made point[0, sin(0)] to be something like [-0.0000, -0.0000], what is of course bad, becuse it takes x value -0.000000000000187... Could anybody help me to push just data with 1 decimal place?

Answer 1

You shouldn't try to adjust the input x values, that's just how computers store numbers.

To show rounded or floored numbers in the tooltip, you'll need to drop the footerFormat, headerFormat, and pointFormat and take complete control of the tooltip using the formatter option. Something like this:

       formatter: function() {
            var s = '<b>'+ Highcharts.numberFormat(this.x,1) +'</b>';                
            $.each(this.points, function(i, point) {
                s += '<br/>'+ point.series.name +': '+
                    Highcharts.numberFormat(this.point.y,4);
            });
            return s;
        }

Should get you want you need. Fiddle here.