Javascript: How to retrieve the number of decimals of a *string* number?
decimal, javascript, numbers, string
Solution
function decimalPlaces(num) {
var match = (''+num).match(/(?:\.(\d+))?(?:[eE]([+-]?\d+))?$/);
if (!match) { return 0; }
return Math.max(
0,
// Number of digits right of decimal point.
(match[1] ? match[1].length : 0)
// Adjust for scientific notation.
- (match[2] ? +match[2] : 0));
}
The extra complexity is to handle scientific notation so
decimalPlaces('.05')
2
decimalPlaces('.5')
1
decimalPlaces('1')
0
decimalPlaces('25e-100')
100
decimalPlaces('2.5e-99')
100
decimalPlaces('.5e1')
0
decimalPlaces('.25e1')
1
Problem
I have a set of string numbers having decimals, for example: `23.456`, `9.450`, `123.01`... I need to retrieve the number of decimals for each number, knowing that they have at least 1 decimal. In other words, the `retr_dec()` method should return the following: ``` retr_dec("23.456") -> 3 retr_dec("9.450") -> 3 retr_dec("123.01") -> 2 ``` Trailing zeros do count as a decimal in this case, unlike in this related question. Is there an easy/delivered method to achieve this in Javascript or should I compute the decimal point position and compute the difference with the string length? Thanks