限制双精度的执行方式 [英] Performing way to limit double accuracy

问题描述

我要管理以下范围内的数字:

I want manage numbers on a range from:

从0,001到999,999

出于表示形式的原因，我想降低一些准确性，仅保留数字的3个最重要的数字.

For representation reasons, I want to drop some of the accuracy keeping only the 3 most important digits of the number.

对于数字123,12，我希望结果为123.

For the number 123,12 I expect the result 123.

对于数字12,123，我希望结果为12,1.

For the number 12,123 I expect the result 12,1.

对于数字0,001，我希望结果为0,001.

For the number 0,001 I expect the result 0,001.

我想到的最好的解决方案是将数字转换为字符串，然后再次以这种方式加倍:

The best solution I thought of is transforming the number into a String, and back again to double, this way:

 number = number*1000;
 String s = new String(number);
 s = s.substr(0, 3) + "000";
 number = Double.parseDouble(s);
 number = number/1000;

这可以完成工作，但是它看起来既性能不好又不优雅. 还有其他更聪明的选择吗? 谢谢！

This does the job but it looks both poorly performing and not elegant. Any more clever alternative? Thank you!

推荐答案

也许使用此正则表达式使代码更简洁?

Perhaps use this RegEx to make the code more concise?

^[,0]{0,6}(\d{3}|\d{2},\d|\d,\d{2})

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