如何用逗号写数字？

function numberWithCommas(x) {
    return x.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

console.log(numberWithCommas(123456789)); // 输出: 123,456,789

def number_with_commas(x):
    return f"{x:,}"

print(number_with_commas(123456789))  # 输出: 123,456,789

import java.text.DecimalFormat;

public class Main {
    public static void main(String[] args) {
        DecimalFormat df = new DecimalFormat("#,###");
        System.out.println(df.format(123456789));  // 输出: 123,456,789
    }
}

using System;

class Program {
    static void Main() {
        int number = 123456789;
        Console.WriteLine(number.ToString("N0"));  // 输出: 123,456,789
    }
}

function formatNumberWithCommas($number) {
    return number_format($number);
}

echo formatNumberWithCommas(123456789);  // 输出: 123,456,789

def number_with_commas(number)
    number.to_s.gsub(/\B(?=(\d{3})+(?!\d))/, ',')
end

puts number_with_commas(123456789)  # 输出: 123,456,789