2020-03-07 千位计数格式

[fanmingfei]

/ **
 * 转换数字为千位计数格式
 * @params {Number} number - 输入数字
 * @renturn {String} 数字对应的千位格式的字符串
 */
function formatToThousands(number) {
 // ...
}
console.log(formatToThousands(123456789)) // 123,456,789

不强制要求使用正则，可以尽量使用正则实现，不太会正则的同学也可以顺便学习一下正则～
不需要考虑浏览器兼容性

[joker1148]

function formatToThousands(number) {
    let num = number.toString()
    let reg = /(?=(\B)(\d{3})+$)/g;
    if(num.split(".").length == 1){
        let res = num.replace(reg,',')
        return res
    }else{
        let fmtNum = num.split(".")
        let big = fmtNum[0]
        let little = fmtNum[1]
        let res = big.replace(reg,',')
        return (res+"."+little)
    }
}
console.log(formatToThousands(123456789.11)) // 123,456,789.11
console.log(formatToThousands(123456789))    // 123,456,789

[IskenHuang]

function formatToThousands(number) {
    return number.toLocaleString()
}
console.log(formatToThousands(123456789)) // 123,456,789

[markmcsong]

function formatToThousands(number) {
  if (!number) return 0
  let str = number.toString()
  // 处理最前部分
  let len = str.length % 3,
    res = `${str.slice(0, len % 3)}`
  sub = str.slice(len % 3)

  // 匹配余下部分
  let reg = /[0-9]{1,3}/g,
    tmp = null
  while ((tmp = reg.exec(sub))) {
    res += "," + tmp
  }
  return len % 3 ? res : res.slice(1)
}
console.log(formatToThousands(123456789)) // 123,456,789
console.log(formatToThousands(12)) // 12

[xiaosen7]

function formatTohousands(number) {

let [int, double = ''] = String(number).split('.');

double = double ? `.${double}` : '';

function reverseStr(str) {
    return str.split('').reverse().join('');
}

let reversedStr = reverseStr(int);

reversedStr = reversedStr.replace(/\d{3}/g, (num) => `${num},`);

let forwardStr = reverseStr(reversedStr);

int = /^-?,/.test(forwardStr) ? forwardStr.replace(/,/, '') : forwardStr;

return int + double;

}

[liuyingbin19222]

小数因为js机制会出现问题，哪一个大佬可以帮助解决一下

function formatToThousands(number){
    var  str = "";
    var arr = new Array();
    var tag = 1000;
    while(1){
        arr.push( number%tag );
        if(tag > number){
            break;
        }
        tag = tag * 1000;
    }
    var newArr = new Array();
    newArr.push(arr[0]);
    for(var i = 0 ; i < arr.length-1;i++){
        newArr.push( (arr[i+1]- arr[i])/(Math.pow(1000,i+1)) );
    }
    newArr = newArr.reverse();
    for(var  i = 0;i < newArr.length;i++){
        if(i == newArr.length -1 ){
            str += newArr[i] + "";
            break;
        }
        str += newArr[i] + "" + ","
    }
    return str;
}

[KobeBeyond]

function formatToThousands(number) {
let p = String(number).split('.')
let q = p[0];
var rgx = /(\d+)(\d{3})/;
while (rgx.test(q)) {
q = q.replace(rgx, '$1' + ',' + '$2');
}
return p.length > 1 ? q + '.' + p[1] : q
}
console.log(formatToThousands(123456789)); // 123,456,789
console.log(formatToThousands(12345678.123)); // 12,345,678.123
console.log(formatToThousands(12)); //12

[SunYiwen]

function formatToThousands(number) {
    number = number.toString();
    if(/\./.test(number)){//存在小数点的情况
        return number.replace(/\d(?=(\d{3})+\.)/g, "$&,");
    }else{//不存在小数点的情况
        return number.replace(/\d(?=(\d{3})+$)/g, "$&,");
    }
}
console.log(formatToThousands(123456789))

[fanmingfei]

function formatToThousands(number) {
    return number.toLocaleString()
}
console.log(formatToThousands(123456789)) // 123,456,789

@IskenHuang 哈哈我的答案被你抢注了。

[fanmingfei]

function formatToThousands(number) {
    const [int,decimal] = number.toString().split('.')
    const len = int.length

    let numberStr = ''
    for(let i = len - 1; i > -1; i--) {
        numberStr = int[i] + numberStr
        if(i !== 0 && (len - i) % 3 === 0) {
            numberStr = ',' + numberStr
        }
        
    }
    return decimal ? `${numberStr}.${decimal}` : numberStr
}

[LiZhaji]

function formatToThousands(number) {
  const [integer, decima] = number.toString().split('.')
  const temp = integer.split('').reverse().join('').replace(/(\d{3})(?=\d)/g, '$1,')
  const formatInt = temp.split('').reverse().join('')
  return formatInt + (decima ? '.' + decima : '')
 }

[FoSuCloud]

		function formatToThousands(num){
			num=String(num);
			var arr=num.indexOf('.')!=-1?num.split('.'):num;
			var str=""
			var len=arr.length>1?arr[0].length:arr.length;
			num=arr.length>1?arr[0]:arr
			if(len>3){
				var mid=(len%3)>0?(len%3):3;
				// 注意，map返回的是数组，所以直接使用加号会有一个逗号存在
				// 所以在第一个数的时候需要额外+,  其他时候不用
				str+=num.slice(0,mid)+num.slice(mid).match(/\d{3}/g).map((item,i) => i==0?(','+item):item)
			}else{
				str+=num
			}
			return arr.length>1?(str+'.'+arr[1]):str
		}
		var obj=formatToThousands(4762322187.64)
		console.log(obj)

[wwwx]

/**
 * 转换数字为千位计数格式
 * @params {Number} number - 输入数字
 * @renturn {String} 数字对应的千位格式的字符串
 */
function formatToThousands(number) {
    if (!Number.isInteger(number)) return false;
    var els = number.toString().split('');
    var arr = []
    for (var i = 0; i < els.length; i++) {
        arr.push(els[i])
        if ((i + 1) % 3 === 0 && i !== els.length - 1) {
            arr.push(',')
        }
    }

    return arr.join('')
}
console.log(formatToThousands(123456789)) // 123,456,789
console.log(formatToThousands(123456789.2233)) // false