我需要显示一个货币值的格式1K等于一千,或1.1K, 1.2K, 1.9K等,如果它不是一个偶数千,否则如果低于一千,显示正常500,100,250等,使用JavaScript格式化的数字?


当前回答

通过消除@martin-sznapka解决方案中的循环,您将减少40%的执行时间。

function formatNum(num,digits) {
    let units = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
    let floor = Math.floor(Math.abs(num).toString().length / 3);
    let value=+(num / Math.pow(1000, floor))
    return value.toFixed(value > 1?digits:2) + units[floor - 1];

}

速度测试(200000随机样本)从这个线程不同的解决方案

Execution time: formatNum          418  ms
Execution time: kFormatter         438  ms it just use "k" no "M".."T" 
Execution time: beautify           593  ms doesnt support - negatives
Execution time: shortenLargeNumber 682  ms    
Execution time: Intl.NumberFormat  13197ms 

其他回答

改进@tfmontague的答案,进一步格式化小数点。33.0k到33k

largeNumberFormatter(value: number): any {
   let result: any = value;

   if (value >= 1e3 && value < 1e6) { result = (value / 1e3).toFixed(1).replace(/\.0$/, '') + 'K'; }
   if (value >= 1e6 && value < 1e9) { result = (value / 1e6).toFixed(1).replace(/\.0$/, '') + 'M'; }
   if (value >= 1e9) { result = (value / 1e9).toFixed(1).replace(/\.0$/, '') + 'T'; }

   return result;
}

通过消除@martin-sznapka解决方案中的循环,您将减少40%的执行时间。

function formatNum(num,digits) {
    let units = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'];
    let floor = Math.floor(Math.abs(num).toString().length / 3);
    let value=+(num / Math.pow(1000, floor))
    return value.toFixed(value > 1?digits:2) + units[floor - 1];

}

速度测试(200000随机样本)从这个线程不同的解决方案

Execution time: formatNum          418  ms
Execution time: kFormatter         438  ms it just use "k" no "M".."T" 
Execution time: beautify           593  ms doesnt support - negatives
Execution time: shortenLargeNumber 682  ms    
Execution time: Intl.NumberFormat  13197ms 

听起来这应该对你有用:

函数 kFormatter(num) { 返回 Math.abs(num) > 999 ?Math.sign(num)*((Math.abs(num)/1000).toFixed(1)) + 'k' : Math.sign(num)*Math.abs(num) } console.log(kFormatter(1200));1.2k console.log(kFormatter(-1200));-1.2k console.log(kFormatter(900));900 console.log(kFormatter(-900));-900

一个更普遍的版本:

function nFormatter(num, digits) { const lookup = [ { value: 1, symbol: "" }, { value: 1e3, symbol: "k" }, { value: 1e6, symbol: "M" }, { value: 1e9, symbol: "G" }, { value: 1e12, symbol: "T" }, { value: 1e15, symbol: "P" }, { value: 1e18, symbol: "E" } ]; const rx = /\.0+$|(\.[0-9]*[1-9])0+$/; var item = lookup.slice().reverse().find(function(item) { return num >= item.value; }); return item ? (num / item.value).toFixed(digits).replace(rx, "$1") + item.symbol : "0"; } /* * Tests */ const tests = [ { num: 0, digits: 1 }, { num: 12, digits: 1 }, { num: 1234, digits: 1 }, { num: 100000000, digits: 1 }, { num: 299792458, digits: 1 }, { num: 759878, digits: 1 }, { num: 759878, digits: 0 }, { num: 123, digits: 1 }, { num: 123.456, digits: 1 }, { num: 123.456, digits: 2 }, { num: 123.456, digits: 4 } ]; tests.forEach(function(test) { console.log("nFormatter(" + test.num + ", " + test.digits + ") = " + nFormatter(test.num, test.digits)); });

支持负数 检查!isFinite 如果你想要最大单位是M,将' K M G T P E Z Y'改为' K M' 基数选项(1K = 1000 / 1K = 1024)


Number.prototype.prefix = function (precision, base) { var units = ' K M G T P E Z Y'.split(' '); if (typeof precision === 'undefined') { precision = 2; } if (typeof base === 'undefined') { base = 1000; } if (this == 0 || !isFinite(this)) { return this.toFixed(precision) + units[0]; } var power = Math.floor(Math.log(Math.abs(this)) / Math.log(base)); // Make sure not larger than max prefix power = Math.min(power, units.length - 1); return (this / Math.pow(base, power)).toFixed(precision) + units[power]; }; console.log('0 = ' + (0).prefix()) // 0.00 console.log('10000 = ' + (10000).prefix()) // 10.00K console.log('1234000 = ' + (1234000).prefix(1)) // 1.2M console.log('-10000 = ' + (-10240).prefix(1, 1024)) // -10.0K console.log('-Infinity = ' + (-Infinity).prefix()) // -Infinity console.log('NaN = ' + (NaN).prefix()) // NaN