how to truncate the float value in javascript

Question

We want to display dynamic value in a table using JavaScript in vb.net. we have define the variable as var rValue.

The expression is rValue = parseFloat(594 * 0.1);

We are getting putput as 59.400000000000006 but we need the output as 59.4 please let us know how to do that .

P.S. We do not want to use tofixed() as it will return the two decimal point for all the values which do not have decimal points.

"`[toFixed()] will return the two decimal point`"??? In which browser? — Teemu, Apr 14 '14 at 06:52
possible duplicate of [Is there a definitive solution to javascript floating-point errors?](http://stackoverflow.com/questions/831687/is-there-a-definitive-solution-to-javascript-floating-point-errors) — Qantas 94 Heavy, Apr 14 '14 at 07:00

Bud Damyanov · Answer 1 · 2014-04-14T06:54:24.587

1

Use the native toPrecision() method:

 <script>   
 var rValue = new Number(59.400000000000006 );
 var n = rValue.toPrecision(3);
 //n will be 59.4 
 </script>

edited Apr 14 '14 at 06:54

answered Apr 14 '14 at 06:49

Bud Damyanov

30,171
6
44
52

1

What if `rValue >= 100`? – Teemu Apr 14 '14 at 07:01

score 1 · Answer 2 · answered Apr 14 '14 at 06:51

1

Use rValue = parseFloat(594 * 0.1).toFixed(2) and if the decimal is .00 remove the decimal places.

e.g.

var num=rValue.split('.')[1];
        if(num==='00')
        {
         rValue=rValue.split('.')[0];
        }

answered Apr 14 '14 at 06:51

Ashutosh

1,000
15
39

score 1 · Answer 3 · answered Apr 14 '14 at 06:53

1

try this:

var rValue = parseFloat(594 * .2);
alert(rValue.toFixed(2).replace(".00",""))

here is demo

answered Apr 14 '14 at 06:53

Zaheer Ahmed

28,160
11
74
110

score 0 · Answer 4 · answered Nov 19 '15 at 11:55

The problem arises from 0.1 not being able to be represented in binary. It actually has an infinite number of decimals, hence every arithmetic operation with this number results in the output being approximate.

You can either opt to use division by a float 10 instead:

var rValue = 594 / 10.0;

or, if this kind of truncation is a recurring issue, you can write a utility function:

/**
* @param {Number} value
* @param {Integer} precision
* @returns {Number}
*/
var truncateFloat = function(value, precision) {
    // Ensure the multiplier is a float
    var pMult = 1.0;
    while (precision--) {
        pMult *= 10;
    }
    // Multiply the value by the precision multiplier, 
    // convert it to int (discarding any pesky leftover decimals) 
    // and float-divide it by the same multiplier
    return ((value * pMult) >> 0) / pMult;
}

Hope this helps a little! :)

score 0 · Answer 5 · answered Jan 27 '22 at 17:11

0

easy arrow function:

const truncate = (number,decimals) =>
Math.trunc(number*Math.pow(10,decimals)) / Math.pow(10,decimals)

answered Jan 27 '22 at 17:11

Rodrigo Solari

1

score -2 · Answer 6 · answered Apr 14 '14 at 07:08

Like This ?

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim rValue As String = 56.40000000006
    Dim charVal() As Char = rValue.ToCharArray()
    Dim getVal As String = Nothing
   '----------Change for decimal places---------
    Dim decimalPlaces As Integer = 2
    Dim decimalPlace As Integer = -1
    Dim realValue As Double = 0
    For Each Val As Char In charVal

        If Char.IsDigit(Val) Then
            getVal &= Val
        Else
            getVal &= "."
        End If

        If getVal.Contains(".") Then
            decimalPlace += 1
        End If

        If decimalPlace = decimalPlaces Then
            Exit For
        End If
    Next
    MsgBox(realValue)
End Sub

how to truncate the float value in javascript

6 Answers6