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integer rounding with parseInt in javascript

Answer 1

+2 A:

Use a combination of parseFloat and Math.round

Math.round(parseFloat("3.567")) //returns 4

[EDIT] Based on your code sample, you don't need a parseInt at all since your argument is already a number. All you need is Math.round

Chetan Sastry 2009-08-04 16:50:48

from painful experience I would always recommend passing in the optional second param to force it to ten base: parseInt( myNum, 10 ) otherwise you can get in a whole world of debug pain when it tries converting strings that start with 0's etc which throw it all out into Hex mode and so on, a real head hurter...!

Pete Duncanson 2009-08-04 17:00:14

I agree, except that parseFloat doesn't have the radix parameter. It is just parseFloat(string).

Chetan Sastry 2009-08-04 17:59:36

Answer 2

+1 A:

leftVal = Math.floor(frequencyValue/30 + 0.5);

cdm9002 2009-08-04 17:05:57

This looks wrong. Floor returns the lower value always, which is specifically what the questioner didn't want.

C. Ross 2009-08-04 17:08:07

That's why you add 0.5

cdm9002 2009-08-04 17:09:01

And the +0.5 rounds it.

Nosredna 2009-08-04 17:09:29

Ah, I see. A rather hackerish way of doing it, but ok.

C. Ross 2009-08-04 17:29:56

Perfectly acceptable technique. This is how round is implemented. From javadoc's Math.round: "The result is rounded to an integer by adding 1/2, taking the floor of the result, and casting the result to type int".

cdm9002 2009-08-04 17:43:04

Answer 3

A:

I think this will solve your problem

<html>
<body>
 <script language="javascript">
  var a = 55/30;
  alert(a.toFixed(0));
 </script>
</body>
</html>

This is a sample code. you can replace my values with your variables.

You can refer the w3schools doc on numbers here. It gives you all the available methods for numbers.

If you want to do more math operations you can use the inbuilt Math Object. You can find the reference here.

Arun P Johny 2009-08-04 17:21:33

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