//方案一
var str = "1234567890";
var newStr = str.replace(/\d/g,function(){
if((str.length-arguments[1]-1)%3===0&&str.length-1!==arguments[1]){
return arguments[0]+",";
}else{
return arguments[0];
}
});
console.log(newStr);//"1,234,567,890"
//方案二
var str = "1234567890";
var newStr = str.replace(/^(\d{1-3})((\d{3})+)$/g,function(){
console.log(arguments);//["1234567890", "1", "234567890", "890", 0, "1234567890", callee: ƒ, Symbol(Symbol.iterator): ƒ]
var part1 = arguments[1];
var part2 = arguments[2];
var newStr = part2.replace(/\d{3}/g,function(){
return ","+arguments[0];
});
return part1 + newStr;
});
// 方案三
var str = "1234567890";
var str1 = str.split("").reverse().join("");
var newStr = str1.replace(/\d{3}/g,function(){
return arguments[0]+","
});
var newStr = newStr.split("").reverse().join("");
console.log(newStr);
//方案四
function fn(str){
var j=0;
for(var i=str.length-1;i>0;i--){
j++;
if(j===3){
str = str.substring(0,i)+","+str.substring(i);
j=0;
}
}
return str;
}
var str = "1234567890";
console.log(fn(str));
//方案一
var str = "1234567890";
var newStr = str.re