我想用JavaScript格式化价格。我想要一个函数,它将浮点作为参数,并返回如下格式的字符串:
"$ 2,500.00"
我该怎么做?
我想用JavaScript格式化价格。我想要一个函数,它将浮点作为参数,并返回如下格式的字符串:
"$ 2,500.00"
我该怎么做?
当前回答
String.prototype.toPrice = function () {
var v;
if (/^\d+(,\d+)$/.test(this))
v = this.replace(/,/, '.');
else if (/^\d+((,\d{3})*(\.\d+)?)?$/.test(this))
v = this.replace(/,/g, "");
else if (/^\d+((.\d{3})*(,\d+)?)?$/.test(this))
v = this.replace(/\./g, "").replace(/,/, ".");
var x = parseFloat(v).toFixed(2).toString().split("."),
x1 = x[0],
x2 = ((x.length == 2) ? "." + x[1] : ".00"),
exp = /^([0-9]+)(\d{3})/;
while (exp.test(x1))
x1 = x1.replace(exp, "$1" + "," + "$2");
return x1 + x2;
}
alert("123123".toPrice()); //123,123.00
alert("123123,316".toPrice()); //123,123.32
alert("12,312,313.33213".toPrice()); //12,312,313.33
alert("123.312.321,32132".toPrice()); //123,312,321.32
其他回答
乔纳森·M的代码对我来说太复杂了,所以我重写了它,在Firefox v30上获得了30%的速度提升,在Chrome v35上获得了60%的速度提升(http://jsperf.com/number-formating2):
Number.prototype.formatNumber = function(decPlaces, thouSeparator, decSeparator) {
decPlaces = isNaN(decPlaces = Math.abs(decPlaces)) ? 2 : decPlaces;
decSeparator = decSeparator == undefined ? "." : decSeparator;
thouSeparator = thouSeparator == undefined ? "," : thouSeparator;
var n = this.toFixed(decPlaces);
if (decPlaces) {
var i = n.substr(0, n.length - (decPlaces + 1));
var j = decSeparator + n.substr(-decPlaces);
} else {
i = n;
j = '';
}
function reverse(str) {
var sr = '';
for (var l = str.length - 1; l >= 0; l--) {
sr += str.charAt(l);
}
return sr;
}
if (parseInt(i)) {
i = reverse(reverse(i).replace(/(\d{3})(?=\d)/g, "$1" + thouSeparator));
}
return i + j;
};
用法:
var sum = 123456789.5698;
var formatted = '$' + sum.formatNumber(2, ',', '.'); // "$123,456,789.57"
通常,有多种方法可以执行相同的操作,但我会避免使用Number.prototype.toLocaleString,因为它可以根据用户设置返回不同的值。
我也不建议扩展Number.prototype-扩展原生对象原型是一种糟糕的做法,因为它可能会与其他人的代码(例如库/框架/插件)发生冲突,并且可能与未来的JavaScript实现/版本不兼容。
我认为正则表达式是解决这个问题的最佳方法,下面是我的实现:
/**
* Converts number into currency format
* @param {number} number Number that should be converted.
* @param {string} [decimalSeparator] Decimal separator, defaults to '.'.
* @param {string} [thousandsSeparator] Thousands separator, defaults to ','.
* @param {int} [nDecimalDigits] Number of decimal digits, defaults to `2`.
* @return {string} Formatted string (e.g. numberToCurrency(12345.67) returns '12,345.67')
*/
function numberToCurrency(number, decimalSeparator, thousandsSeparator, nDecimalDigits){
//default values
decimalSeparator = decimalSeparator || '.';
thousandsSeparator = thousandsSeparator || ',';
nDecimalDigits = nDecimalDigits == null? 2 : nDecimalDigits;
var fixed = number.toFixed(nDecimalDigits), //limit/add decimal digits
parts = new RegExp('^(-?\\d{1,3})((?:\\d{3})+)(\\.(\\d{'+ nDecimalDigits +'}))?$').exec( fixed ); //separate begin [$1], middle [$2] and decimal digits [$4]
if(parts){ //number >= 1000 || number <= -1000
return parts[1] + parts[2].replace(/\d{3}/g, thousandsSeparator + '$&') + (parts[4] ? decimalSeparator + parts[4] : '');
}else{
return fixed.replace('.', decimalSeparator);
}
}
这可能奏效:
function format_currency(v, number_of_decimals, decimal_separator, currency_sign){
return (isNaN(v)? v : currency_sign + parseInt(v||0).toLocaleString() + decimal_separator + (v*1).toFixed(number_of_decimals).slice(-number_of_decimals));
}
没有循环,没有正则表达式,没有数组,没有奇异条件。
一种仅满足原始要求的极简方法:
function formatMoney(n) {
return "$ " + (Math.round(n * 100) / 100).toLocaleString();
}
@丹尼尔·马格廖拉:你说得对。以上是一个仓促而不完整的实施。以下是正确的实施方式:
function formatMoney(n) {
return "$ " + n.toLocaleString().split(".")[0] + "."
+ n.toFixed(2).split(".")[1];
}
这是我的。。。
function thousandCommas(num) {
num = num.toString().split('.');
var ints = num[0].split('').reverse();
for (var out=[],len=ints.length,i=0; i < len; i++) {
if (i > 0 && (i % 3) === 0) out.push(',');
out.push(ints[i]);
}
out = out.reverse() && out.join('');
if (num.length === 2) out += '.' + num[1];
return out;
}