如何在javascript中截断浮点值

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 .

PS 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.

Answer 1

Use the native toPrecision() method:

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

Answer 2

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

eg

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

Answer 3

try this:

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

here is demo

Answer 4

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! :)

Answer 5

easy arrow function:

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

Answer 6

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