Javascript验证数组元素的总和净为零

Question

I have a requirement to validate the sum of the elements of my array net to zero. The array could contain positive or negative values. The array elements are 1164.44,-2919.42,2500.59,-5197.15,4451.54 My code without using toFixed is

    var v_total=0;
   var v;
   var varray  = document.getElementsByName('f02');
   for (var i = 0; i < varray.length; i++)
   {

      v = (isNaN(parseFloat(varray[i].value)))?0:varray[i].value;
     v_total = parseFloat(cv_total) + parseFloat(v);

   }

    v_total = (isNaN(cv_total))?0:cv_total;

which results with the sum 9.094947017729282e-13 If I add it using a calc, it does net to zero Searched the forum and understand that it is the behaviour of floating numbers. Despite using toFixed, I am unable to get the sum zero . Also the number of digits after the decimal could vary and is not always 2 Request any advice on how to workaround this

Thanks

Answer 1

This works fine, what seems to be the problem?

var n=[1164.44,-2919.42,2500.59,-5197.15,4451.54];
s=n.reduce(function(x,y) {
    return parseFloat((x+y).toFixed(2));
});
console.log(s);

JSFiddle here: http://jsfiddle.net/91g4qb0z/

Answer 2

You can use reduce() and toPrecision():

  var arr =[1164.44,-2919.4204,2500.5904,-5197.151,4451.541]; var result = arr.reduce(function(a, b){ return +a.toPrecision(15) + +b.toPrecision(15) }); alert(result);