Finding out if a number is a whole number or a floating point value

JavaScript
1

Hi,

does anyone know a good way to find out if a number is a whole number or a floating
point value?

I’ve thought that i can grab the number, convert it to a string and check the string
for a period…if it has a period then its a floating point number.

This method seems hacky to me and was wondering if there’s some other way of doing it?

Thanks

2

To me the method you mentioned doesn’t look hackish at all. JavaScript, unlike other languages like PHP/C, does not differentiate between integer values and floating-point values. It knows only one numeric type: Number. So, you won’t find functions like is_int() or do something like if(getType(number) == ‘int’) in JavaScript. So, manually checking the presence of the decimal character is the only solution that comes to mind.

3

Hi,

Yes I know about the lack of distinction between intergers and floating point values in javascript …that’s why i asked :slight_smile: Thanks for the clarification.

4

You can use the modulus operator.

For example 5 % 1 will return 0

However, 5.1 % 1 will return 0.1

so you could use

so if somevalue % 1 == 0 … then you know that somevalue is an integer otherwise it is fp

for testing type in 5%1 in google search to calculate the result. Then type in 5.1%1 in a google search to see that result. Try different combinations of numbers and you will understand what is going on.

hope this helps

5

OR

<script type="text/javascript">
    var num = 12;
    if(parseInt(num) == num){
        alert('Integer');
    }
    else if(parseFloat(num) == num){
        alert('Float');
    }
    else{
        alert('Invalid');
    } 
</script>
6

Is it the number you’re checking or the data type? Do you want 12.0 to be an integer or a float?

7

JavaScript doesn’t have integers or floats - just numbers so the data type either way is the same. That is why the original poster asked the question.

The %1 solution given would be the easiest most efficient way of calculating it as it doesn’t need a function call to work it out.

8

Sorry for the confusion. The question I was asking was whether the program needs to distinguish between numbers being entered as integers or floating point. Does it care if a user enters 12.0 as opposed to 12?