Convert String with Dot or Comma as decimal separator to number in JavaScript

问题

An input element contains numbers a where comma or dot is used as decimal separator and space may be used to group thousands like this:

'1,2'
'110 000,23'
'100 1.23'

How would one convert them to a float number in the browser using JavaScript?

jQuery and jQuery UI are used. Number(string) returns NaN and parseFloat() stops on first space or comma.

回答1:

Do a replace first:

parseFloat(str.replace(',','.').replace(' ',''))

回答2:

The perfect solution

accounting.js is a tiny JavaScript library for number, money and currency formatting.

Check this for ref

回答3:

I realise I'm late to the party, but I wanted a solution for this that properly handled digit grouping as well as different decimal separators for currencies. As none of these fully covered my use case I wrote my own solution which may be useful to others:

function parsePotentiallyGroupedFloat(stringValue) {
    stringValue = stringValue.trim();
    var result = stringValue.replace(/[^0-9]/g, '');
    if (/[,\.]\d{2}$/.test(stringValue)) {
        result = result.replace(/(\d{2})$/, '.$1');
    }
    return parseFloat(result);
}

This should strip out any non-digits and then check whether there was a decimal point (or comma) followed by two digits and insert the decimal point if needed.

It's worth noting that I aimed this specifically for currency and as such it assumes either no decimal places or exactly two. It's pretty hard to be sure about whether the first potential decimal point encountered is a decimal point or a digit grouping character (e.g., 1.542 could be 1542) unless you know the specifics of the current locale, but it should be easy enough to tailor this to your specific use case by changing \d{2}$ to something that will appropriately match what you expect to be after the decimal point.

回答4:

You could replace all spaces by an empty string, all comas by dots and then parse it.

var str = "110 000,23";
var num = parseFloat(str.replace(/\s/g, "").replace(",", "."));
console.log(num);

I used a regex in the first one to be able to match all spaces, not just the first one.

回答5:

This is the best solution

http://numeraljs.com/

numeral().unformat('0.02'); = 0.02

回答6:

What about:

parseFloat(str.replace(' ', '').replace('.', '').replace(',', '.'));

回答7:

All the other solutions require you to know the format in advance. I needed to detect(!) the format in every case and this is what I end up with.

function detectFloat(source) {
    let float = accounting.unformat(source);
    let posComma = source.indexOf(',');
    if (posComma > -1) {
        let posDot = source.indexOf('.');
        if (posDot > -1 && posComma > posDot) {
            let germanFloat = accounting.unformat(source, ',');
            if (Math.abs(germanFloat) > Math.abs(float)) {
                float = germanFloat;
            }
        } else {
            // source = source.replace(/,/g, '.');
            float = accounting.unformat(source, ',');
        }
    }
    return float;
}

This was tested with the following cases:

        const cases = {
            "0": 0,
            "10.12": 10.12,
            "222.20": 222.20,
            "-222.20": -222.20,
            "+222,20": 222.20,
            "-222,20": -222.20,
            "-2.222,20": -2222.20,
            "-11.111,20": -11111.20,
        };

Suggestions welcome.

回答8:

Here's a self-sufficient JS function that solves this (and other) problems for most European/US locales (primarily between US/German/Swedish number chunking and formatting ... as in the OP). I think it's an improvement on (and inspired by) Slawa's solution, and has no dependencies.

function realParseFloat(s)
{
    s = s.replace(/[^\d,.-]/g, ''); // strip everything except numbers, dots, commas and negative sign
    if (navigator.language.substring(0, 2) !== "de" && /^-?(?:\d+|\d{1,3}(?:,\d{3})+)(?:\.\d+)?$/.test(s)) // if not in German locale and matches #,###.######
    {
        s = s.replace(/,/g, ''); // strip out commas
        return parseFloat(s); // convert to number
    }
    else if (/^-?(?:\d+|\d{1,3}(?:\.\d{3})+)(?:,\d+)?$/.test(s)) // either in German locale or not match #,###.###### and now matches #.###,########
    {
        s = s.replace(/\./g, ''); // strip out dots
        s = s.replace(/,/g, '.'); // replace comma with dot
        return parseFloat(s);
    }
    else // try #,###.###### anyway
    {
        s = s.replace(/,/g, ''); // strip out commas
        return parseFloat(s); // convert to number
    }
}

回答9:

From number to currency string is easy through Number.prototype.toLocaleString. However the reverse seems to be a common problem. The thousands separator and decimal point may not be obtained in the JS standard.

In this particular question the thousands separator is a white space " " but in many cases it can be a period "." and decimal point can be a comma ",". Such as in 1 000 000,00 or 1.000.000,00. Then this is how i convert it into a proper floating point number.

var price = "1 000.000,99",
    value = +price.replace(/(\.|\s)|(\,)/g,(m,p1,p2) => p1 ? "" : ".");
console.log(value);

So the replacer callback takes "1.000.000,00" and converts it into "1000000.00". After that + in the front of the resulting string coerces it into a number.

This function is actually quite handy. For instance if you replace the p1 = "" part with p1 = "," in the callback function, an input of 1.000.000,00 would result 1,000,000.00

来源：https://stackoverflow.com/questions/7431833/convert-string-with-dot-or-comma-as-decimal-separator-to-number-in-javascript