Get Number of Decimal Places with Javascript

How would I calculate the number of decimal places (not digits) of a real number with Javascript?

function countDecimals(number) {



}

For example, given 245.395, it should return 3.

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

1

What should 245.0 return?

– RobG
Nov 22 '14 at 21:32

add a comment |

How would I calculate the number of decimal places (not digits) of a real number with Javascript?

function countDecimals(number) {



}

For example, given 245.395, it should return 3.

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

1

What should 245.0 return?

– RobG
Nov 22 '14 at 21:32

add a comment |

How would I calculate the number of decimal places (not digits) of a real number with Javascript?

function countDecimals(number) {



}

For example, given 245.395, it should return 3.

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

How would I calculate the number of decimal places (not digits) of a real number with Javascript?

function countDecimals(number) {



}

For example, given 245.395, it should return 3.

javascript

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

edited Nov 22 '14 at 21:40

Andrei Volgin

34.4k53150

asked Nov 22 '14 at 20:49

Octocat

1741315

asked Nov 22 '14 at 20:49

Octocat

1741315

asked Nov 22 '14 at 20:49

Octocat

1741315

1

What should 245.0 return?

– RobG
Nov 22 '14 at 21:32

add a comment |

1

What should 245.0 return?

– RobG
Nov 22 '14 at 21:32

What should 245.0 return?

– RobG
Nov 22 '14 at 21:32

add a comment |

6 Answers
6

active

oldest

votes

Like this:

var val = 37.435345;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

add a comment |

The main idea is to convert a number to string and get the index of "."

var x = 13.251256;

var text = x.toString();

var index = text.indexOf(".");

alert(text.length - index - 1);

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

add a comment |

You can use a simple function that splits on the decimal place (if there is one) and counts the digits after that. Since the decimal place can be represented by '.' or ',' (or maybe some other character), you can test for that and use the appropriate one:

function countPlaces(num) {

    var sep = String(23.32).match(/D/)[0];

    var b = String(num).split(sep);

  return b[1]? b[1].length : 0;

}



console.log(countPlaces(2.343)); // 3

console.log(countPlaces(2.3));   // 1

console.log(countPlaces(343.0)); // 0

console.log(countPlaces(343));   // 0

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

add a comment |

Here is a method that does not rely on converting anything to string:

function getDecimalPlaces(x,watchdog)

{

    x = Math.abs(x);

    watchdog = watchdog || 20;

    var i = 0;

    while (x % 1 > 0 && i < watchdog)

    {

        i++;

        x = x*10;

    }

    return i;

}

Note that the count will not go beyond watchdog value (defaults to 20).

answered Apr 19 '15 at 10:36

jahu

3,64812347

add a comment |

var value = 888;

var valueLength = value.toString().length;

answered Nov 23 '18 at 1:43

Jun Bin

646

1

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

add a comment |

Based on Gosha_Fighten's solution, for compatibility with integers:

function countPlaces(num) {

    var text = num.toString();

    var index = text.indexOf(".");

    return index == -1 ? 0 : (text.length - index - 1);

}

answered Dec 12 '18 at 9:13

LePatay

9217

add a comment |

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6 Answers
6

active

oldest

votes

6 Answers
6

active

oldest

votes

Like this:

var val = 37.435345;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

add a comment |

Like this:

var val = 37.435345;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

add a comment |

Like this:

var val = 37.435345;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

Like this:

var val = 37.435345;

var countDecimals = function(value) {

    if (Math.floor(value) !== value)

        return value.toString().split(".")[1].length || 0;

    return 0;

}

countDecimals(val);

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

answered Nov 22 '14 at 20:51

Alex Filatov

1,76232228

add a comment |

The main idea is to convert a number to string and get the index of "."

var x = 13.251256;

var text = x.toString();

var index = text.indexOf(".");

alert(text.length - index - 1);

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

add a comment |

The main idea is to convert a number to string and get the index of "."

var x = 13.251256;

var text = x.toString();

var index = text.indexOf(".");

alert(text.length - index - 1);

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

add a comment |

The main idea is to convert a number to string and get the index of "."

var x = 13.251256;

var text = x.toString();

var index = text.indexOf(".");

alert(text.length - index - 1);

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

The main idea is to convert a number to string and get the index of "."

var x = 13.251256;

var text = x.toString();

var index = text.indexOf(".");

alert(text.length - index - 1);

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

answered Nov 22 '14 at 20:53

Gosha_Fighten

2,43411222

add a comment |

function countPlaces(num) {

    var sep = String(23.32).match(/D/)[0];

    var b = String(num).split(sep);

  return b[1]? b[1].length : 0;

}



console.log(countPlaces(2.343)); // 3

console.log(countPlaces(2.3));   // 1

console.log(countPlaces(343.0)); // 0

console.log(countPlaces(343));   // 0

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

add a comment |

function countPlaces(num) {

    var sep = String(23.32).match(/D/)[0];

    var b = String(num).split(sep);

  return b[1]? b[1].length : 0;

}



console.log(countPlaces(2.343)); // 3

console.log(countPlaces(2.3));   // 1

console.log(countPlaces(343.0)); // 0

console.log(countPlaces(343));   // 0

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

add a comment |

function countPlaces(num) {

    var sep = String(23.32).match(/D/)[0];

    var b = String(num).split(sep);

  return b[1]? b[1].length : 0;

}



console.log(countPlaces(2.343)); // 3

console.log(countPlaces(2.3));   // 1

console.log(countPlaces(343.0)); // 0

console.log(countPlaces(343));   // 0

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

function countPlaces(num) {

    var sep = String(23.32).match(/D/)[0];

    var b = String(num).split(sep);

  return b[1]? b[1].length : 0;

}



console.log(countPlaces(2.343)); // 3

console.log(countPlaces(2.3));   // 1

console.log(countPlaces(343.0)); // 0

console.log(countPlaces(343));   // 0

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

answered Nov 22 '14 at 21:39

RobG

98.1k19106145

add a comment |

Here is a method that does not rely on converting anything to string:

function getDecimalPlaces(x,watchdog)

{

    x = Math.abs(x);

    watchdog = watchdog || 20;

    var i = 0;

    while (x % 1 > 0 && i < watchdog)

    {

        i++;

        x = x*10;

    }

    return i;

}

Note that the count will not go beyond watchdog value (defaults to 20).

answered Apr 19 '15 at 10:36

jahu

3,64812347

add a comment |

Here is a method that does not rely on converting anything to string:

function getDecimalPlaces(x,watchdog)

{

    x = Math.abs(x);

    watchdog = watchdog || 20;

    var i = 0;

    while (x % 1 > 0 && i < watchdog)

    {

        i++;

        x = x*10;

    }

    return i;

}

Note that the count will not go beyond watchdog value (defaults to 20).

answered Apr 19 '15 at 10:36

jahu

3,64812347

add a comment |

Here is a method that does not rely on converting anything to string:

function getDecimalPlaces(x,watchdog)

{

    x = Math.abs(x);

    watchdog = watchdog || 20;

    var i = 0;

    while (x % 1 > 0 && i < watchdog)

    {

        i++;

        x = x*10;

    }

    return i;

}

Note that the count will not go beyond watchdog value (defaults to 20).

answered Apr 19 '15 at 10:36

jahu

3,64812347

Here is a method that does not rely on converting anything to string:

function getDecimalPlaces(x,watchdog)

{

    x = Math.abs(x);

    watchdog = watchdog || 20;

    var i = 0;

    while (x % 1 > 0 && i < watchdog)

    {

        i++;

        x = x*10;

    }

    return i;

}

Note that the count will not go beyond watchdog value (defaults to 20).

answered Apr 19 '15 at 10:36

jahu

3,64812347

answered Apr 19 '15 at 10:36

jahu

3,64812347

answered Apr 19 '15 at 10:36

jahu

3,64812347

answered Apr 19 '15 at 10:36

jahu

3,64812347

add a comment |

var value = 888;

var valueLength = value.toString().length;

answered Nov 23 '18 at 1:43

Jun Bin

646

1

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

add a comment |

var value = 888;

var valueLength = value.toString().length;

answered Nov 23 '18 at 1:43

Jun Bin

646

1

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

add a comment |

var value = 888;

var valueLength = value.toString().length;

answered Nov 23 '18 at 1:43

Jun Bin

646

var value = 888;

var valueLength = value.toString().length;

answered Nov 23 '18 at 1:43

Jun Bin

646

answered Nov 23 '18 at 1:43

Jun Bin

646

answered Nov 23 '18 at 1:43

Jun Bin

646

answered Nov 23 '18 at 1:43

Jun Bin

646

1

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

add a comment |

1

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

Please add some explanation and context.

– mjk
Nov 23 '18 at 4:45

add a comment |

Based on Gosha_Fighten's solution, for compatibility with integers:

function countPlaces(num) {

    var text = num.toString();

    var index = text.indexOf(".");

    return index == -1 ? 0 : (text.length - index - 1);

}

answered Dec 12 '18 at 9:13

LePatay

9217

add a comment |

Based on Gosha_Fighten's solution, for compatibility with integers:

function countPlaces(num) {

    var text = num.toString();

    var index = text.indexOf(".");

    return index == -1 ? 0 : (text.length - index - 1);

}

answered Dec 12 '18 at 9:13

LePatay

9217

add a comment |

Based on Gosha_Fighten's solution, for compatibility with integers:

function countPlaces(num) {

    var text = num.toString();

    var index = text.indexOf(".");

    return index == -1 ? 0 : (text.length - index - 1);

}

answered Dec 12 '18 at 9:13

LePatay

9217

Based on Gosha_Fighten's solution, for compatibility with integers:

function countPlaces(num) {

    var text = num.toString();

    var index = text.indexOf(".");

    return index == -1 ? 0 : (text.length - index - 1);

}

answered Dec 12 '18 at 9:13

LePatay

9217

answered Dec 12 '18 at 9:13

LePatay

9217

answered Dec 12 '18 at 9:13

LePatay

9217

answered Dec 12 '18 at 9:13

LePatay

9217

add a comment |

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