用 js 實現千位分隔符

function thousandBitSeparator(num) {
  //return a && b means "return a if a is falsy, return b if a is truthy".
    return num && (num.toString().indexOf('.') != -1 ? num.toString().replace(/(\d)(?=(\d{3})+\.)/g, function($0, $1) {
        return $1 + ",";
    }) : num.toString().replace(/(\d)(?=(\d{3}))/g, function($0, $1) {
        return $1 + ",";
    }));
}

 

更多將輸入的復雜字符串轉為預期結果的方法，請參見 千位分隔符的完整攻略