java（初学者）将科学记数法转换为十进制
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java (beginner) converting scientific notation to decimal
提问by hibc
if
如果
double d = 1.999e-4
I want my output to be 0.0001999.
我希望我的输出为 0.0001999。
How can I do it?
我该怎么做？
采纳答案by RP-
NumberFormat formatter = new DecimalFormat("###.#####");
String f = formatter.format(d);
You can explore the sub classes of NumberFormatclass to know more details.
您可以探索类的子类NumberFormat以了解更多详细信息。
回答by Adam Arold
You can do it like this:
你可以这样做：
double d = 1.999e-4;
NumberFormat nf = NumberFormat.getInstance();
nf.setMinimumFractionDigits(7);
System.out.println(nf.format(d));
Check out the documentation of NumberFormat's methods to format your doubleas you see fit.
查看NumberFormat的方法的文档以double根据您的需要设置格式。
DecimalFormatis a special case of NumberFormatas its constructor states, I don't think that you need its functionality for your case. Check out their documentation if you are confused. Use the factory method getInstance()of NumberFormatfor your convenience.
DecimalFormat是一种特殊情况，NumberFormat正如其构造函数所述，我认为您不需要它的功能。如果您感到困惑，请查看他们的文档。使用工厂方法getInstance()的NumberFormat为您提供方便。
回答by Harsh Chaturvedi
I suppose there is a method in BigDecimal Class called toPlainString().
e.g. if the the BigDecimal is 1.23e-8 then the method returns 0.0000000124.
我想 BigDecimal 类中有一个方法叫做toPlainString(). 例如，如果 BigDecimal 是 1.23e-8，则该方法返回 0.0000000124。
BigDecimal d = new BigDecimal("1.23E-8");
System.out.println(d.toPlainString());
Above code prints 0.0000000123, then you can process the string as per your requirement.
上面的代码打印 0.0000000123，然后您可以根据您的要求处理字符串。
回答by specialscope
If all you want is to print like that.
如果你只想像那样打印。
System.out.printf("%1$.10f", d);
you can change 10f, 10=number of decimal places you want.
您可以更改 10f, 10=您想要的小数位数。
回答by cmg_george
Take a look over
看一看
java.text.DecimalFormat
and
和
java.text.DecimalFormatSymbols
