将逗号(分组分隔符)添加到数字而不修改小数位数?

问题描述

我正在尝试设置字符串格式以在3位数字组之间添加逗号

I'm trying to format a string to add commas between 3 digit groups

EG:

1200.20 >> 1,200.20
15000   >> 15,000

我试图弄清楚如何使用DecimalFormat，到目前为止，我一直在使用自己的脚本，该脚本似乎过于复杂.我不知道该怎么做，使用#只是隐藏结尾的零，而使用0会将它们添加到数字中.

I'm trying to figure out how to do it with DecimalFormat, to this point I have been using a script of my own that seems overly complicated. I cannot figure out how to do it, using # simply hides trailing zeroes and using 0 adds them to the number.

这就是我现在正在尝试的内容:

This is what I'm trying right now:

DecimalFormat df = new DecimalFormat("###,###.####", new DecimalFormatSymbols(Locale.US));
resultStr = df.format(Double.valueOf(resultStr));

我确定它一定很容易，但是我不确定该怎么做.我不必使用DecimalFormat进行操作，我只是认为这将是更简单的方法.如何简单地添加逗号而不用任何方式修改小数?

I'm sure it must be easy but I'm not sure how to do it. I don't have to do it with DecimalFormat, I just thought it would be the easier way. How can I simply add the commas without modifying the decimals in any way?

推荐答案

您应该使用NumberFormat对象并将其设置为使用分组.像

You should use a NumberFormat object and set it to use grouping. Something like

import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;

public class NumberFormatEg {
   public static void main(String[] args) {
      NumberFormat myFormat = NumberFormat.getInstance();
      myFormat.setGroupingUsed(true);

      double[] numbers = { 11220.00, 232323232.24, 121211.55, 102.121212 };

      for (double d : numbers) {
         System.out.println(myFormat.format(d));
      }
      System.out.println();

      DecimalFormat decimalFormat = new DecimalFormat("#.00");
      decimalFormat.setGroupingUsed(true);
      decimalFormat.setGroupingSize(3);

      for (double d : numbers) {
         System.out.println(decimalFormat.format(d));
      }

      System.out.println("\nFor Germany");

      NumberFormat anotherFormat = NumberFormat
            .getNumberInstance(Locale.GERMAN);
      if (anotherFormat instanceof DecimalFormat) {
         DecimalFormat anotherDFormat = (DecimalFormat) anotherFormat;
         anotherDFormat.applyPattern("#.00");
         anotherDFormat.setGroupingUsed(true);
         anotherDFormat.setGroupingSize(3);

         for (double d : numbers) {
            System.out.println(anotherDFormat.format(d));
         }

      }

      System.out.println("\nFor US:");

      anotherFormat = NumberFormat.getNumberInstance(Locale.US);
      if (anotherFormat instanceof DecimalFormat) {
         DecimalFormat anotherDFormat = (DecimalFormat) anotherFormat;
         anotherDFormat.applyPattern("#.00");
         anotherDFormat.setGroupingUsed(true);
         anotherDFormat.setGroupingSize(3);

         for (double d : numbers) {
            System.out.println(anotherDFormat.format(d));
         }

      }
   }
}

返回:

11,220
232,323,232.24
121,211.55
102.121

11,220.00
232,323,232.24
121,211.55
102.12

For Germany
11.220,00
232.323.232,24
121.211,55
102,12

For US:
11,220.00
232,323,232.24
121,211.55
102.12

这样做的一个优点是解决方案可以是特定于语言环境的.

An advantage of this is that the solution can be locale specific.

已编辑
现在显示一个带有DecimalFormat对象的示例.请注意，如果使用此选项，则应设置分组大小.

Edited
Now shows an example with a DecimalFormat object. Note that you should set the grouping size if you use this.

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