给数字添加千位符
更多描述
//=> '123'
numberThousands(123);
//=> '1,234,567'
numberThousands(1234567);问题追问：
- 如果考虑正负数应该如何处理
- 如果考虑小数应该如何处理?
//=> '123'
numberThousands(123);
//=> '1,234,567'
numberThousands(1234567);
// 可以处理正负数
// => '-123,456'
numberThousands(123456);
// 可以处理小数
// => '-123,456.123456789'
numberThousands(123456.123456789);Issue 欢迎在 Gtihub Issue 中回答此问题: Issue 610 (opens in a new tab)
Author 回答者: shfshanyue (opens in a new tab)
千位符替换可由正则 /(\d)(?=(\d\d\d)+(?!\d))/ 进行匹配
function numberThousands(number, thousandsSeperator = ",") {
return String(number).replace(
/(\d)(?=(\d\d\d)+(?!\d))/g,
"$1" + thousandsSeperator,
);
}删除的正则或许有点复杂，如果对字符串反转，可以来一个简单的正则
function numberThousands(number, thousandsSeperator = ",") {
const reverse = (str) => str.split("").reverse().join("");
const str = reverse(String(number)).replace(
/(\d\d\d)(?=\d)/g,
"$1" + thousandsSeperator,
);
return reverse(str);
}如果你写不出来正则，也可由一段简单的代码实现
function numberThousands(number, thousandsSeperator = ",") {
const s = String(number);
let r = "";
for (let i = s.length - 1; i >= 0; i--) {
const seperator = (s.length - i - 1) % 3 ? "" : thousandsSeperator;
r = `${s[i]}${seperator}${r}`;
}
return r.slice(0, -1);
}同时，再提供一个取巧的办法：
Intl.NumberFormat(undefined, {
style: "decimal",
maximumFractionDigits: 20,
}).format(number);
number.toLocaleString(undefined, { maximumFractionDigits: 20 });Author 回答者: haotie1990 (opens in a new tab)
如果你写不出来正则，也可由一段简单的代码实现
function toString(number, thousandsSeperator = ",") { const s = String(number); let r = ""; for (let i = s.length - 1; i >= 0; i--) { const seperator = (s.length - i - 1) % 3 ? "" : thousandsSeperator; r = `${s[i]}${seperator}${r}`; } return r.slice(0, -1); }
这个有点问题，如果是带有小数的数字，会有转换异常
Author 回答者: Asarua (opens in a new tab)
function toString(number) {
return number.toLocaleString();
}哈哈哈哈，取个巧
Author 回答者: haotie1990 (opens in a new tab)
function numberThousands(number) {
const numberStr = String(number);
let result = "";
let [interger, decimal] = numberStr.split(".");
while (interger.length > 3) {
// 倒数三位数字
let subStr = interger.substring(interger.length - 3);
interger = interger.replace(subStr, "");
result = `,${subStr}${result}`;
}
if (interger.length) {
result = `${interger}${result}`;
}
return result + (decimal ? `.${decimal}` : "");
}Author 回答者: VirgoHxy (opens in a new tab)
function numberThousands(num) {
let result = "";
let str = String(num);
let length = str.length;
for (let index = length - 1; index >= 0; index--) {
const element = str[index];
result = element + result;
if (index && (length - index) % 3 == 0) {
result = "," + result;
}
}
return result;
}Author 回答者: bigbigDreamer (opens in a new tab)
const numberThousands = (number) => {
const strNum = Number.parseFloat(number).toString();
const [interSection, restSection] = strNum.split(".");
const reverseInter = interSection.split("").reverse().join("");
const finalInter = reverseInter
.match(/(\d{0,3})+?/g)
.filter((x) => x)
.map((item) => item.split("").reverse().join(""))
.reverse()
.join(",");
return `${finalInter}${restSection ? `.${restSection}` : ""}`;
};Author 回答者: okkjoo (opens in a new tab)
删除的正则或许有点复杂，如果对字符串反转，可以来一个简单的正则
function numberThousands(number, thousandsSeperator = ",") { const reverse = (str) => str.split("").reverse().join(""); const str = reverse(String(number)).replace( /\d\d\d(?!\d)/g, "$1" + thousandsSeperator, ); return reverse(str); }
错了，应该是 ?= 而不是 ?!
```js
function numberThousands(number, thousandsSeperator = ",") {
const reverse = (str) => str.split("").reverse().join("");
const str = reverse(String(number)).replace(
/(\d\d\d)(?=\d)/g,
"$1" + thousandsSeperator
);
return reverse(str);
}