我试图在JavaScript中打印一个整数，用逗号作为千位分隔符。例如，我想将数字1234567显示为“1234567”。我该怎么做？
我是这样做的：
函数编号WithCommas（x）{x=x.toString（）；var模式=/（-？\d+）（\d｛3｝）/；while（模式测试（x））x=x.replace（模式，“$1，$2”）；返回x；}console.log（数字与逗号（1000））
有没有更简单或更优雅的方法？如果它也可以与浮点运算一起使用，那就很好了，但这不是必须的。它不需要特定于区域设置来决定句点和逗号。
当前回答
我已经调整了您的代码以在TextBox（输入类型=“text”）中工作，这样我们就可以在不丢失光标的情况下实时输入和删除数字。如果您在删除时选择范围，它也会起作用。您可以自由使用箭头和起始/结束按钮。谢谢你节省了我的时间！
//function controls number format as "1,532,162.3264321"
function numberWithCommas(x) {
var e = e || window.event;
if (e.keyCode >= '35' && e.keyCode <= '40') return; //skip arrow-keys
var selStart = x.selectionStart, selEnd = x.selectionEnd; //save cursor positions
var parts = x.value.toString().split(".");
var part0len = parts[0].length; //old length to check if new ',' would be added. Need for correcting new cursor position (+1 to right).
//if user deleted ',' - remove previous number instead (without selection)
if (x.selectionLength == 0 && (e.keyCode == 8 || e.keyCode == 46)) {//if pressed 8-backspace or 46-delete button
var delPos = parts[0].search(/\d{4}/);
if (delPos != -1) {//if found 4 digits in a row (',' is deleted)
if (e.keyCode == 8) {//if backspace flag
parts[0] = parts[0].slice(0, selStart - 1) + parts[0].slice(selEnd, parts[0].length);
selEnd--;
if (selStart > selEnd) selStart = selEnd;
} else {
parts[0] = parts[0].slice(0, selStart) + parts[0].slice(selEnd + 1, parts[0].length);
selStart++;
if (selEnd < selStart) selEnd = selStart;
}
}
}
var hasMinus = parts[0][0] == '-';
parts[0] = (hasMinus ? '-' : '') + parts[0].replace(/[^\d]*/g, ""); //I'd like to clear old ',' to avoid things like 1,2,3,5,634.443216
parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ","); //sets ',' between each 3 digits
if (part0len < parts[0].length) { //move cursor to right if added new ','
selStart++;
selEnd++;
} else if (part0len > parts[0].length) { //..or if removed last one ','
selStart--;
selEnd--;
}
x.value = parts.join(".");
x.setSelectionRange(selStart, selEnd); //restoring cursor position
}
function saveSelectionLength(x) {
x.selectionLength = x.selectionEnd - x.selectionStart;
}
要使用它，只需添加两个事件-onKeyUp和onKeyDown
<asp:TextBox runat="server" ID="val" Width="180px" onKeyUp="numberWithCommas(this);" onKeyDown="saveSelectionLength(this);"/>
其他回答
Intl.NumberFormat（国际数字格式）
本机JS函数。支持IE11、Edge、最新Safari、Chrome、Firefox、Opera、iOS上的Safari和Android上的Chrome。
var number = 3500;
console.log(new Intl.NumberFormat().format(number));
// → '3,500' if in US English locale
我提出了另一个解决方案。
第一个代码是这样的。
function formatNumber(number) {
if (number < 1000) {
return String(number);
}
if (number < 1000000) {
let numbers = String(number).split('');
numbers.splice(-3, 0, ',');
return numbers.join('');
}
if (number < 1000000000) {
let numbers = String(number).split('');
numbers.splice(-3, 0, ',');
numbers.splice(-7, 0, ',');
return numbers.join('');
}
if (number < 1000000000000) {
let numbers = String(number).split('');
numbers.splice(-3, 0, ',');
numbers.splice(-7, 0, ',');
numbers.splice(-11, 0, ',');
return numbers.join('');
}
throw new Error(`number: ${number} is too big`);
}
这段代码很长，不可伸缩，但它很有效，因为它检查的是数字本身，而不是从数字转换的字符串的长度。
所以我基于这个想法转换成了整洁的代码。（你可以再放大12个以防出错。）
function formatNumber(number) {
let commas = -1;
for (let n3 = 3; n3 <= 12; n3 += 3) {
commas++;
const max = Math.pow(10, n3);
if (number < max) {
let numbers = String(number).split('');
for (let i = 0; i < commas; i++) {
numbers.splice(-(3 * (i + 1) + i), 0, ',');
}
return numbers.join('');
}
}
throw new Error(`number: ${number} is too big`);
}
这里有一个简单的函数，它为千个分隔符插入逗号。它使用数组函数而不是RegEx。
/**
* Format a number as a string with commas separating the thousands.
* @param num - The number to be formatted (e.g. 10000)
* @return A string representing the formatted number (e.g. "10,000")
*/
var formatNumber = function(num) {
var array = num.toString().split('');
var index = -3;
while (array.length + index > 0) {
array.splice(index, 0, ',');
// Decrement by 4 since we just added another unit to the array.
index -= 4;
}
return array.join('');
};
CodeSandbox链接，示例如下：https://codesandbox.io/s/p38k63w0vq
我已经调整了您的代码以在TextBox（输入类型=“text”）中工作，这样我们就可以在不丢失光标的情况下实时输入和删除数字。如果您在删除时选择范围，它也会起作用。您可以自由使用箭头和起始/结束按钮。谢谢你节省了我的时间！
//function controls number format as "1,532,162.3264321"
function numberWithCommas(x) {
var e = e || window.event;
if (e.keyCode >= '35' && e.keyCode <= '40') return; //skip arrow-keys
var selStart = x.selectionStart, selEnd = x.selectionEnd; //save cursor positions
var parts = x.value.toString().split(".");
var part0len = parts[0].length; //old length to check if new ',' would be added. Need for correcting new cursor position (+1 to right).
//if user deleted ',' - remove previous number instead (without selection)
if (x.selectionLength == 0 && (e.keyCode == 8 || e.keyCode == 46)) {//if pressed 8-backspace or 46-delete button
var delPos = parts[0].search(/\d{4}/);
if (delPos != -1) {//if found 4 digits in a row (',' is deleted)
if (e.keyCode == 8) {//if backspace flag
parts[0] = parts[0].slice(0, selStart - 1) + parts[0].slice(selEnd, parts[0].length);
selEnd--;
if (selStart > selEnd) selStart = selEnd;
} else {
parts[0] = parts[0].slice(0, selStart) + parts[0].slice(selEnd + 1, parts[0].length);
selStart++;
if (selEnd < selStart) selEnd = selStart;
}
}
}
var hasMinus = parts[0][0] == '-';
parts[0] = (hasMinus ? '-' : '') + parts[0].replace(/[^\d]*/g, ""); //I'd like to clear old ',' to avoid things like 1,2,3,5,634.443216
parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ","); //sets ',' between each 3 digits
if (part0len < parts[0].length) { //move cursor to right if added new ','
selStart++;
selEnd++;
} else if (part0len > parts[0].length) { //..or if removed last one ','
selStart--;
selEnd--;
}
x.value = parts.join(".");
x.setSelectionRange(selStart, selEnd); //restoring cursor position
}
function saveSelectionLength(x) {
x.selectionLength = x.selectionEnd - x.selectionStart;
}
要使用它，只需添加两个事件-onKeyUp和onKeyDown
<asp:TextBox runat="server" ID="val" Width="180px" onKeyUp="numberWithCommas(this);" onKeyDown="saveSelectionLength(this);"/>
与@elias zamaria和@t.j.crowder相关
Safari浏览器的负面外观是不能使用<。所以，应该是（？！\.\d*）
function numberWithCommas(n) {
return n.toString().replace(/\B(?!\.\d*)(?=(\d{3})+(?!\d))/g, ",");
}
它适用于Safari和Firefox
