I have this :
i=4.568;
document.write(i.toFixed(2));
output :
4.57
But i don't want to round the last number to 7 , what can i do?
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When you're working with binary floating point, things like this can happen.Pointy– Pointy2012-04-19 13:56:15 +00:00Commented Apr 19, 2012 at 13:56
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@Pointy: No; he just doesn't want rounding.SLaks– SLaks2012-04-19 13:58:48 +00:00Commented Apr 19, 2012 at 13:58
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Yes, but my point is that in general when dealing with floating point you can't guarantee that a constant you type in will end up being what you think it is, rounding or no rounding, primarily because 2 and 5 are relatively prime :-)Pointy– Pointy2012-04-19 14:00:37 +00:00Commented Apr 19, 2012 at 14:00
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3 Answers
Use simple math instead;
document.write(Math.floor(i * 100) / 100);
You can stick it in your own function for reuse;
function myToFixed(i, digits) {
var pow = Math.pow(10, digits);
return Math.floor(i * pow) / pow;
}
document.write(myToFixed(i, 2));
3 Comments
AMIN Gholibeigian
The function returns nothing ..!
AMIN Gholibeigian
should be : document.write(Math.floor(i * 100)/ 100);
Steven.Chang
This is not a correct method due to floating point number precision problem. Ex: try 0.29, you will get 0.28 instead
A slightly convoluted approach:
var i=4.568,
iToString = i + '';
i = parseFloat(iToString.match(/\d+\.\d{2}/));
console.log(i);
This effectively takes the variable i and converts it to a string, and then uses a regex to match the numbers before the decimal point and the two following that decimal point, using parseFloat() to then convert it back to a number.
References:
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