用特定数字浮点精度 [英] Float precision with specific numbers

问题描述

下面的值给我错误的精度。只用特定的数字来观察。这可能是一个浮动表示的问题，但想知道具体原因。

  String m =154572.49; //\"154,572.49\" ; 
 Float f = Float.parseFloat（m）; 
 System.out.println（f）; 
  

打印输出是 154572.48 154572.49 。

解决方案

与您在Java中输入内容完全相同，请使用 BigDecimal 而不是float。

浮点数对于小数本质上是不准确的，因为许多以十进制结尾的数字（如0.1）是二进制和浮点数的重复数字以二进制形式存储。

The following value gives me wrong precision. It is observed with only specific numbers. It might be a floating representation problem, but wanted to know the specific reason.

String m = "154572.49"; //"154,572.49";
Float f = Float.parseFloat(m);
System.out.println(f);

The output it is printing is 154572.48 instead of 154572.49.

解决方案

If you want decimal numbers to come out as exactly as you entered them in Java, use BigDecimal instead of float.

Floating point numbers are inherently inaccurate for decimals because many numbers that terminate in decimal (e.g. 0.1) are recurring numbers in binary and floating point numbers are stored as a binary representation.

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