Check whether a float number contains decimals or not

Question

How can I check whether a float number contains decimals like 2.10, 2.45, 12382.66 and not 2.00 , 12382.00. I want to know if the number is "round" or not. How can I do that programmatically?

By looking at them? If you want a programmatic solution, then give us more information. — skaffman, Jan 12 '11 at 11:51

score 61 · Answer 1 · edited Jul 11 '18 at 16:33

61

Using modulus will work:

if(num % 1 != 0) do something!
// eg. 23.5 % 1 = 0.5

edited Jul 11 '18 at 16:33

Himanshu

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61

answered Feb 21 '13 at 07:22

Knights

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1
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24

5

Great answer, but this will not work in [PHP](http://php.net/manual/en/language.operators.arithmetic.php): "Operands of modulus are converted to integers (by stripping the decimal part) before processing." – Daan Aug 24 '16 at 09:44

score 8 · Answer 2 · answered Oct 11 '13 at 18:38

8

I use this c function for objective c

BOOL CGFloatHasDecimals(float f) {
    return (f-(int)f != 0);
}

answered Oct 11 '13 at 18:38

Alex Markman

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score 5 · Answer 3 · edited May 23 '17 at 12:02

5

If you care only about two decimals, get the remainder by computing bool hasDecimals = (((int)(round(x*100))) % 100) != 0;

In generic case get a fractional part as described in this topic and compare it to 0.

edited May 23 '17 at 12:02

Community

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1

answered Jan 12 '11 at 11:55

Eugene Mayevski 'Callback

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2

This worked beautifully for me. I'm using Objective-C btw. As long as you know how many decimals you care about evaluating, this is simple and does the job. And you can modify it by by multiplying 10 by the power of how many decimal spots you care about, to replace the occurrences of "100" in the above sample, to make it even more flexible. – idStar Feb 26 '12 at 18:35

score 3 · Answer 4 · answered Jan 12 '11 at 11:57

3

You could do this:

  float num = 23.345f;
  int intpart = (int)num;
  float decpart = num - intpart;
  if(decpart == 0.0f)
  {
    //Contains no decimals
  }
  else
  {
     //Number contains decimals
  }

answered Jan 12 '11 at 11:57

Owen

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1
1
9

score 2 · Answer 5 · answered Dec 23 '13 at 16:52

import java.lang.Math;
public class Main {
    public static void main(String arg[]){
        convert(50.0f);
        convert(13.59f);

    }

    private static void convert(float mFloat){
        if(mFloat - (int)mFloat != 0)
            System.out.println(mFloat);
        else
            System.out.println((int)mFloat);
    }
}

score 1 · Answer 6 · answered Oct 18 '19 at 08:09

1

PHP solution:

function hasDecimals($x)
{
    return floatval($x) - intval($x) != 0;
}

answered Oct 18 '19 at 08:09

Zsolti

1,571
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score 0 · Answer 7 · answered Nov 16 '19 at 11:51

0

In Scala you can use isWhole() or isValidInt() to check if number has no fractional part:

object Example {
  def main(args: Array[String]) = {

    val hasDecimals = 3.14.isWhole //false
    val hasDecimals = 3.14.isValidInt//false

  }
}

answered Nov 16 '19 at 11:51

Dmytro Melnychuk

2,285
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Check whether a float number contains decimals or not

7 Answers7

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